Thereza Christina Monteiro Lima | Universidade Federal de Santa Catarina - UFSC (Federal University of Santa Catarina) (original) (raw)

Papers by Thereza Christina Monteiro Lima

Naunyn-Schmiedeberg's Archives of Pharmacology, 2014

European Neuropsychopharmacology, 2006

Psychopharmacology, 2008

Polygala sabulosa, a folk medicine, presents dihydrostyryl-2-pyrones (DST) and styryl-2-pyrones (... more Polygala sabulosa, a folk medicine, presents dihydrostyryl-2-pyrones (DST) and styryl-2-pyrones (STY), compounds structurally similar to kavalactones. Our previous study showed that the ethyl acetate fraction (EA) and these constituents present anxiolytic-like, hypno-sedative, and anticonvulsant effects in mice. This study investigated the role of benzodiazepine binding site (BDZ-bs) in the central effects of either EA or three DST (1, 2, and 3) and three STY (4, 5, and 7), using in vivo and in vitro assays. In the elevated plus-maze (EPM), flumazenil (FMZ), a BDZ antagonist, partially blocked the anxiolytic-like effect of DST-3 or STY-4 and STY-7, but not DST-1. Using electroencephalogram (EEG), EA protected against pentylenetetrazole (PTZ)-induced convulsion in rats, an effect partially blocked by FMZ, suggesting the participation of the BDZ-bs in this action. EA also protected against the maximal electroshock (MES)-induced convulsions in mice, a profile distinct from diazepam (DZP). DST and STY compounds inhibited the [(3)H]-flunitrazepam ([(3)H]-FNZ) binding to BDZ-bs in rat cortical synaptosomes with K (i) higher than 100 microM (DST-1), 41.7 microM (DST-2), 35.8 microM (DST-3), 90.3 microM (STY-4), 31.0 microM (STY-5) and 70.0 microM (STY-7). In the saturation assay, DST-3 and STY-7 competitively inhibited the binding of [(3)H]-FNZ to BDZ-bs with a significant decrease in apparent affinity (K (d)) and no change in maximal binding (B (max)). The present data support a partial BDZ-bs mediation of the anxiolytic-like and anticonvulsant effects of EA of P. sabulosa and its main isolated constituents, DST and STY.

Extensive evidence indicates the influence of the cholinergic system on emotional processing. Pre... more Extensive evidence indicates the influence of the cholinergic system on emotional processing. Previous findings provided new insights into the underlying mechanisms of long-term anxiety, showing that rats injected with a single systemic dose of pilocarpine—a muscarinic receptor (mAChR) agonist—displayed persistent anxiogenic-like responses when evaluated in different behavioral tests and time-points (24 h up to 3 months later). Herein, we investigated whether the pilocarpine-induced long-term anxiogenesis modulates the HPA axis function and the putative involvement of NMDA receptors (NMDARs) following mAChRs activation. Accordingly, adult male Wistar rats presented anxiogenic-like behavior in the elevated plus-maze (EPM) after 24 h or 1 month of pilocarpine injection (150 mg/kg, i.p.). In these animals, mAChR activation disrupted HPA axis function inducing a long-term increase of corticosterone release associated with a reduced expression of hippocampal GRs, as well as consistently decreased NMDAR subunits expression. Furthermore, in another group of rats injected with memantine–an NMDARs antagonist (4 mg/kg, i.p.)–prior to pilocarpine, we found inhibition of anxiogenic-like behaviors in the EPM but no further alterations in the pilocarpine-induced NMDARs downregulation. Our data provide evidence that behavioral anxiogenesis induced by mAChR activation effectively yields short-and long-term alterations in hippocampal NMDARs expression associated with impairment of hippocampal inhibitory regulation of HPA axis activity. This is a novel mechanism associated with anxiety-like responses in rats, which comprise a putative target to future transla-tional studies.

While anxiety disorders are the brain disorders with the highest prevalence and constitute a majo... more While anxiety disorders are the brain disorders with the highest prevalence and constitute a major burden for society, a considerable number of affected people are still treated insufficiently. Thus, in an attempt to identify potential new anxiolytic drug targets, neuropeptides have gained considerable attention in recent years. Compared to classical neurotransmitters they often have a regionally restricted distribution and may bind to several distinct receptor subtypes. Neuropeptide Y (NPY) is a highly conserved neuropeptide that is specifically concentrated in limbic brain areas and signals via at least 5 different G-protein-coupled receptors. It is involved in a variety of physiological processes including the modulation of emotional-affective behaviors. An anxiolytic and stress-reducing property of NPY is supported by many preclinical studies. Whether NPY may also interact with processing of learned fear and fear extinction is comparatively unknown. However, this has considerable relevance since pathological, inappropriate and generalized fear expression and impaired fear extinction are hallmarks of human post-traumatic stress disorder and a major reason for its treatment-resistance. Recent evidence from different laboratories emphasizes a fearreducing role of NPY, predominantly mediated by exogenous NPY acting on Y1 receptors. Since a reduction of fear expression was also observed in Y1 receptor knockout mice, other Y receptors may be equally important. By acting on Y2 receptors, NPY promotes fear extinction and generates a long-term suppression of fear, two important preconditions that could support cognitive behavioral therapies in human patients. A similar effect has been demonstrated for the closely related pancreatic polypeptide (PP) when acting on Y4 receptors. Preliminary evidence suggests that NPY modulates fear in particular by activation of Y1 and Y2 receptors in the basolateral and central amygdala, respectively. In the basolateral amygdala, NPY signaling activates inhibitory G protein-coupled inwardly-rectifying potassium channels or suppresses hyperpolarization-induced I(h) currents in a Y1 receptordependent fashion, favoring a general suppression of neuronal activity. A more complex situation has been described for the central extended amygdala, where NPY reduces the frequency of inhibitory and excitatory postsynaptic currents. In particular the inhibition of long-range central amygdala output neurons may result in a Y2 receptor-dependent suppression of fear. The role of NPY in processes of learned fear and fear extinction is, however, only beginning to emerge, and multiple questions regarding the relevance of endogenous NPY and different receptor subtypes remain elusive. Y2 receptors may be of particular interest for future studies, since they are the most prominent Y receptor subtype in the human brain and thus among the most promising therapeutic drug targets when translating preclinical evidence to potential new therapies for human anxiety disorders.

Neuropeptides have an important role in several psychiatric conditions. Among them, neuropeptide ... more Neuropeptides have an important role in several psychiatric conditions. Among them, neuropeptide Y (NPY) seems to be essential to modulate some features of stress-related disorders. Post-traumatic stress disorder (PTSD), characterized by inappropriate fear generalization to safe situations may be modulated by NPY manipulation since this neuropeptide is involved in the promotion of coping with stress. Experimentally, coping strategies have been obtained after exposure in enriched environment (EE) rather than standard one. Thus, in the present study we aimed to assess whether short-term EE situation and NPY-Y1 receptor (Y1r) modulation may affect the extinction of contextual fear conditioning, an experimental approach to PTSD. Here we show that EE-rats have the contextual fear extinction facilitated, and this facilitation was reverted by central infusion of BIBO3304, a nonpeptide Y1r antagonist. In addition, protein analysis revealed an upregulation of hippocampal Y1r in conditioned EE-rats, but no changes were observed in EE-rats that were not conditioned. Our results demonstrated that protective properties of EE on fear extinction can be regulated, at least in part, by activation of NPY-signaling through Y1r within hippocampus, an area that plays a major role in contextual memories. Overall, the activation of Y1r is important to promote better and faster perception of self-location (context), and to reduce fear generalization in rats exposed to EE.

Aims: Piperazinic derivatives have therapeutic potential by acting as analgesic, antidepressant-l... more Aims: Piperazinic derivatives have therapeutic potential by acting as analgesic, antidepressant-like, anticonvulsant and antipsychotic in preclinical studies. In order to develop new drugs to treat mental disorders, we designed and synthesized the 4-(1-phenyl-1H-pyrazol-4-ylmethyl)-piperazine-1-carboxylic acid ethyl ester (PPMP), a new piperazine derivative with putative activities on central nervous system that seems to involve serotonergic system. Materials and methods: In order to investigate the antidepressant-like activity of PPMP, mice were treated acutely and tested in the forced swimming test (FST) and tail suspension test. Pretreatment with the 5-HT synthesis inhibitor p-chlorophenylalanine (PCPA, 100 mg/kg, i.p., 4 days), and the non-selective blocker of catecholamine synthesis α-methyl para-tyrosine (AMPT, 100 mg/kg, i.p.) were used to assay the involvement of serotonergic and catecholaminergic systems. " Ex vivo " monoamine oxidase (MAO) enzymatic assay and quantification of hippocampal level of brain derived neurotrophic factor (BDNF) were carried out. Key findings: PPMP reduced the immobility time in both tests. PCPA or AMPT (100 mg/kg, i.p.) pretreatment blocked the effects of PPMP, thereby suggesting the involvement of serotonergic and catecholaminergic systems in the antidepressant-like effect of PPMP. PPMP did not inhibit the activity of MAO. Moreover, after 14 days of treatment, PPMP 15 mg/kg/day induced antidepressant-like effect and increased hippocampal level of BDNF. None of the treatments in this study altered the locomotor activity in the open field test. Significance: In conclusion, PPMP demonstrates antidepressant-like effect that involve both serotonergic and catecholaminergic systems without inhibition of MAO activity. PPMP administration increased the hippocampal levels of BDNF.

In the current study we showed that oral administration of an aqueous extract of Passiflora quadr... more In the current study we showed that oral administration of an aqueous extract of Passiflora quadrangularis L., Passifloraceae, pericarp results in a significant prolongation of the sleep duration in mice evaluated in the ethyl ether-induced hypnosis test which indicates sedative effects. Apigenin, the main flavonoid of the extract, induced a similar sedative response when applied alone, at a dose equivalent to that found in the extract, suggesting that apigenin is mediating the sedative effects of P. quadrangularis extract. In addition, the sedative effect of apigenin was blocked by pretreatment with the benzodiazepine antagonist flumazenil (1 mg/kg), suggesting an interaction of apigenin with gamma-aminobutyric acid type A (GABA A) receptors. However, apigenin at concentrations 0.1–50 M failed to enhance GABA-induced currents through GABA A receptors (1 2 2S) expressed in Xenopus oocytes. Nevertheless, based on our results, we suggest that the in vivo sedative effect of the P. quadrangularis extract and its main flavonoid apigenin maybe be due to an enhancement of the GABAergic system.

without significant change in plasma NPY. Within 30 min of infusion FAM-labeled NPY was detected ... more without significant change in plasma NPY. Within 30 min of infusion FAM-labeled NPY was detected in multiple regions of the brain. When NPY infusion was given 30 min before or immediately after the exposure to single prolonged stress (SPS) rodent PTSD model, it greatly attenuated, and in many cases prevented, the rise in anxiety, hyperarousal and depressive-like behaviors observed weeks after exposure to the traumatic stress. NPY was able to attenuate development of many SPS-triggered neuroendocrine and molecular impairments. NPY prevented SPS triggered induction of CRH, glucocorticoid receptor (GR) and FKBP5 mRNAs and the reduction of phosphorylated GR in the mediobasal hypothalamus, and the increased expression and phosphorylation of GR in the ventral hippocampus. It also prevented the increased expression of NE-biosynthetic enzymes and their sensitization to a stress reminder and to mild novel stressor. It also inhibited the elevation of CRH in the amygdala and the induction of CRHR1 in the brain noradrenergic system. Moreover, single intranasal infusion of NPY to rats a week after SPS stressors, when PTSD symptoms were already developed was anxiolytic, when tested 2 h, and even more so 2 days later. It also had antidepressive-like properties. These findings provide proof of concept for potential of intranasal NPY for PTSD and comorbid disorders of traumatic stress (supported by grant DM102281 from the US Army). Neuropeptide Y (NPY) has been proposed as a potential target for anxiety treatment by modulating its actions through Y 1 and Y 2 receptors. Indeed, cumulative evidence has shown that NPY modulates corticosterone (CORT) secretion, a key component of anxiety and stress. However, the mechanism of action of NPY on CORT is not completely understood. In particular, acute CORT administration induces an increase in anxiogenic-related behavior in the elevated plus maze (EPM) that parallels with neuronal hypertrophy in the basolateral amygdala (BLA). Whether these CORT effects can be prevented by modulation of NPY receptors has not been studied yet. In the present study, we aimed to investigate the behavioral and neuro-protective effects of the Y 1-like receptor agonist, [Leu 31 Pro 34 ] PYY, the Y 1 receptor antagonist, BIBO3304, the Y 2 receptor agonist PYY3-36, and the Y 2 receptor antagonist, BIIE0246 in CORT-treated rats. While BIIE0246 increased the number of entries in the open arm of the EPM in CORT treated rats, PYY3-36 decreased the number of entries in control animals. Neither [Leu 31 Pro 34 ] PYY nor BIBO3304 produced behavioral modifications in CORT treated or control rats. Furthermore, BIIE0246 reduced the neuronal hypertrophy in the BLA in CORT-treated rats without inducing neuronal modifications in control rats. Thus, these results showed that BIIE0246 reverses the behavioral and neuronal deleterious effects of CORT treatment and suggest that selective antagonism of the Y 2 receptor subtype have a potential use in the treatment of anxiety-related disorders. The encoding of emotional memories may occur inappropriately resulting in pathological conditions such as the Post-Traumatic Stress Disorder. Neuropeptide Y is largely expressed on dorsal hippocampus (DH), the main cerebral area related to memory formation. Here we investigated the role of NPY system in the DH of adult male Wistar rats tested on contextual fear conditioning. Institutional Ethical Committee approved all the procedures (PP798). One week after DH bilateral guide cannula implantation, each animal was tested. Drugs were delivered 5 min before the training session to evaluate the fear memory acquisition (ACQ) and immediately after the training to evaluate memory consolidation (CON). Freezing behavior was reported 3 h after conditioning (short term memory — Test A1) and 24 h later (long term memory — Test A2). Effects of drugs on anxiety-like levels were measured on the elevated plus-maze (EPM). Independent groups were used. Only rats that presented successful bilaterally surgeries were considered. During ACQ and CON Test A1, two-way ANOVA showed no significant differences between groups which presented high freezing behavior. During ACQ and CON Test A2, two-way ANOVA showed significant differences between groups. In both cases Newman–Keuls post hoc test showed that NPY 3 and 10 pmol, LP-NPY 1 pmol (Y1 agonist) groups expressed less freezing compared to other groups. Moreover, this effect was prevented by previous BIBO3304 (Y1 antagonist) administration. On EPM, one-way ANOVA showed no statistical difference for the time spent in the open-arm and enclosed-arms entries. Altogether, our results suggest the NPY infusion into DH may impair aversive memory consolidation through Y1 receptor activation, without interfering neither with anxiety levels or locomotor activity.

Os produtos naturais têm servido de inspiração para o desenvolvimento de vários produtos pela ind... more Os produtos naturais têm servido de inspiração para o desenvolvimento de vários produtos pela indústria farmacêutica local e mundial. O objetivo do presente trabalho foi avaliar a atividade farmacológica preliminar do extrato aquoso das folhas secas de Tynanthus micranthus, usando o teste hipocrático em camundongos, como uma ferramenta para direcionar estudos farmacológicos futuros, bem como avaliar os custos envolvidos na execução deste estudo. A T. micranthus Corr. Méllo ex K. Schum, conhecida popularmente como cipó-cravo, é facilmente encontrada na região Noroeste do Estado do Paraná, Brasil, sendo utilizada pela população como calmante e analgésica. No entanto, existem poucos trabalhos científicos com esta espécie vegetal. O cálculo do custo contábil foi realizado para simular o valor gasto por uma empresa privada na realização destas atividades de Pesquisa e Desenvolvimento. Nossos resultados mostram que além do baixo custo, o teste hipocrático proporciona resultados importantes para a decisão da via de administração, toxicidade aguda, efeitos com altas doses e por diferentes vias, além de fornecer informações sobre a latência para os efeitos observados. Com essas informações e uma análise fitoquímica mais aprofundada, isolando e identificando os compostos majoritários, é possível avaliar na literatura a relação composto x atividade farmacológica direcionando de forma mais assertiva as pesquisas a serem realizadas. De maneira geral, apresentamos dados inéditos da espécie estudada (T. micranthus), mostrando uma estratégia de triagem farmacológica simples e de baixo custo para a pesquisa de plantas medicinais nativas que apresentem informações restritas na literatura e que possam servir para o desenvolvimento de novos produtos farmacêuticos. Palavras-chave: Bignoniaceae; plantas medicinais; teste hipocrático ABSTRACT: Natural products have been an inspiration for developing several pharmaceutical products by the local and world industry. The aim of the present study was to evaluate the preliminar pharmacological activity of the aqueous extract from leaves of Tynanthus micranthus, using the hippocratic test in mice as a tool to guide the pharmacological studies, as well as to estimate the costs involved in this process. T. micranthus Corr. Méllo ex K. Schum, popularly known as cipó-cravo, is easily found in the Northwest region of the State of Paraná, Brazil, being used as tranquilizer and analgesic folk medicine. However, there are just few scientific studies on this plant species. The evaluation of financial costs was performed to simulate the value spent by a private company in the realization of these Research & Development activities. Our results show that the Hippocratic test is a low cost test, and produces important results to take the decision about the route of administration, the acute toxicity, pharmacological effects, giving information about the latency to observe the effects. This information plus a further phytochemical analysis, isolating and identifying the major constituents, besides the evaluation in the literature about the relationship between compounds X pharmacological activities, guiding the research to be done. Overall, In the present study we presented an unpublished pharmacological activity (analgesic) for T. micranthus, showing a strategy of a simple and of low cost pharmacological screening to the research of native medicinal plants that present few information in the literature and that could be useful for the development of new pharmaceutical products.

• NK 1 receptor antagonist's FK888 did not alter emotional responses in CA 1 or LSD. • Infusion o... more • NK 1 receptor antagonist's FK888 did not alter emotional responses in CA 1 or LSD. • Infusion of FK888 into CA 1 inhibits long-term anxiogenic responses induced by PILO. • PILO changes anxiogenic responses modulated by SP-NK 1 receptor signaling in CA 1. a b s t r a c t Recent evidence supports a role for the substance P (SP) in the control of anxiety and epilepsy disorders. Aversive stimuli alter SP levels and SP immunoreactivity in limbic regions, suggesting that changes in SP-NK 1 receptor signaling may modulate the neuronal excitability involved in seizures and anxiogenesis. The involvement of NK 1 receptors of the dorsal hippocampus and lateral septum in the anxiogenic-like effects induced by a single injection of pilocarpine (PILO) was examined in non-convulsive rats evaluated in the elevated plus-maze (EPM). Male Wistar rats were systemically injected with methyl-scopolamine (1 mg/kg) followed 30 min later by saline or PILO (350 mg/kg) and only rats that did not present status epilepticus were used. One month later, vehicle or FK888 (100 pmol) – an NK 1 receptor antagonist – were infused in the dorsal hippocampus or the lateral septum of the rats and then behaviorally evaluated in the EPM. Previous treatment with PILO decreased the time spent in and the frequency of entries in the open arms of the EPM, besides altering risk-assessment behaviors such as the number of unprotected head-dipping, protected stretch-attend postures and the frequency of open-arms end activity, showing thus a long-lasting anxiogenic-like profile. FK888 did not show any effect per se but inhibited the anxiogenic responses induced by PILO when injected into the dorsal hippocampus, but not into the lateral septum. Our data suggest that SP-NK 1 receptor signaling of the dorsal hippocampus is involved in the anxiogenic-like profile induced by PILO in rats evaluated in the EPM test.

S288 P.1.h. Basic and clinical neuroscience − Animal behaviour more effectively in RLA rats than ... more S288 P.1.h. Basic and clinical neuroscience − Animal behaviour more effectively in RLA rats than RHA rats (P < 0.05, two-way ANOVA followed by Bonferroni's post hoc test).

Neuropeptide Y (NPY) is the most abundant peptide in the central nervous system (CNS) and is dens... more Neuropeptide Y (NPY) is the most abundant peptide in the central nervous system (CNS) and is densely localized in the brain regions involved in stress, memory, fear and anxiety. Although previous research supports a role for NPY in the mediation of rodent and human emotional behavior, there is currently a lack of information on the effects of low doses of NPY that could have a potential therapeutic advantage, minimizing side-effects such as cognition impairment or sedation. Herein, we assessed the effects of intracerebroventricular (i.c.v.) administration of low doses of NPY, and of the Y1-agonist Leu31Pro34-NPY (LP-NPY) on contextual fear conditioning (CFC), as they have no effect on unconditioned anxiety-like, locomotor activity and non-emotional memory. NPY (3 pmol) and LP-NPY (1 pmol) inhibited freezing behavior when administered in the acquisition or consolidation stages, indicating a reduction of fear. When injected in the extinction phase, only NPY inhibited freezing behavior on CFC. Pre-treatment with the Y1-antagonist BIBO3304 before NPY and LP-NPY was able to prevent the inhibition of fear responses induced by both NPY agonists. Taken together, our results demonstrate robust fear-inhibiting effects of i.c.v. injection of NPY on contextual fear conditioning in rats, a response that is mediated, at least in part, by the Y1 receptor. Moreover, these treatments were unable to change locomotor activity or to show an anxiolytic-like effect, as evaluated in an open-field and an elevated plus-maze. This specific fear reduction effect may underlie resilience systems in the CNS and has potential therapeutic relevance in PTSD.

h i g h l i g h t s NPY prevented A␤ 1-40 -induced depressive-like responses in mice. NPY prevent... more h i g h l i g h t s NPY prevented A␤ 1-40 -induced depressive-like responses in mice. NPY prevented A␤ 1-40 -induced spatial memory impairments in mice. The blockade of Y2 receptors prevented the protective effects of NPY on A␤ 1-40 -treated mice. NPY blunted A␤ 1-40 -induced lipid peroxidation in the hippocampus and prefrontal cortex. a b s t r a c t Neuropeptide Y (NPY) is a 36-amino acid peptide widely distributed in the central nervous system (CNS) that has been associated with the modulation of several functions including food intake, learning and memory, mood and neuroprotection. There is great interest in understanding the role of NPY in the deleterious effects induced by the central accumulation of amyloid-␤ (A␤) peptides, a pathological hallmark of Alzheimer's disease (AD). Herein, we evaluated the effects of a single intracerebroventricular (i.c.v.) administration of NPY (0.0234 mol/L) 15 min prior to the i.c.v. injection of aggregated A␤ 1-40 peptide (400 pmol/mouse) in behavioral and neurochemical parameters related to oxidative stress in mice. Pretreatment with NPY prevented A␤ 1-40 -induced depressive-like responses and spatial memory impairments evaluated in the tail suspension and object location tasks, respectively. The protective effects of NPY on spatial memory of A␤ 1-40 -treated mice were abolished by the pretreatment with the selective Y2 receptor antagonist BIIE0246. On the other hand, the administration of NPY and A␤ 1-40 did not alter the performance of the animals in the elevated plus-maze and open field arena, indicating lack of effects on anxiety state and locomotor function. Although A␤ 1-40 infusion did not change hippocampal and cortical glutathione peroxidase (GPx) activity and glutathione (GSH) levels, A␤ 1-40 -infused animals showed an increased lipid peroxidation in hippocampus and prefrontal cortex that were blunted by NPY administration. These findings indicate that central administration of NPY prevents A␤ 1-40 -induced depressive-like behavior and spatial memory deficits in mice and that this response is mediated, at least in part, by the activation of Y2 receptors and prevention of oxidative stress.

Ghrelin is a gastric hormone that stimulates growth hormone (GH) secretion and food intake to reg... more Ghrelin is a gastric hormone that stimulates growth hormone (GH) secretion and food intake to regulate energy homeostasis and body weight by binding to its receptor, GH secretagogue receptor (GHSR1a), which is most highly expressed in the pituitary and hy-pothalamus. Nowadays there is considerable evidence showing that the GHSR1a is also expressed in numerous extra-hypothalamic neu-ronal populations and the physiological role of ghrelin is by far wider than considered before including learning and memory, anxiety, depression and neuroprotection. The present review attempts to provide a comprehensive picture of the role of ghrelin in the central nervous system and to highlight recent findings showing its potential as an innovative therapeutic agent in neurodegenerative diseases including Alzheimer's disease and Parkinson's disease.

Naunyn-Schmiedeberg's Archives of Pharmacology, 2014

European Neuropsychopharmacology, 2006

Psychopharmacology, 2008

Polygala sabulosa, a folk medicine, presents dihydrostyryl-2-pyrones (DST) and styryl-2-pyrones (... more Polygala sabulosa, a folk medicine, presents dihydrostyryl-2-pyrones (DST) and styryl-2-pyrones (STY), compounds structurally similar to kavalactones. Our previous study showed that the ethyl acetate fraction (EA) and these constituents present anxiolytic-like, hypno-sedative, and anticonvulsant effects in mice. This study investigated the role of benzodiazepine binding site (BDZ-bs) in the central effects of either EA or three DST (1, 2, and 3) and three STY (4, 5, and 7), using in vivo and in vitro assays. In the elevated plus-maze (EPM), flumazenil (FMZ), a BDZ antagonist, partially blocked the anxiolytic-like effect of DST-3 or STY-4 and STY-7, but not DST-1. Using electroencephalogram (EEG), EA protected against pentylenetetrazole (PTZ)-induced convulsion in rats, an effect partially blocked by FMZ, suggesting the participation of the BDZ-bs in this action. EA also protected against the maximal electroshock (MES)-induced convulsions in mice, a profile distinct from diazepam (DZP). DST and STY compounds inhibited the [(3)H]-flunitrazepam ([(3)H]-FNZ) binding to BDZ-bs in rat cortical synaptosomes with K (i) higher than 100 microM (DST-1), 41.7 microM (DST-2), 35.8 microM (DST-3), 90.3 microM (STY-4), 31.0 microM (STY-5) and 70.0 microM (STY-7). In the saturation assay, DST-3 and STY-7 competitively inhibited the binding of [(3)H]-FNZ to BDZ-bs with a significant decrease in apparent affinity (K (d)) and no change in maximal binding (B (max)). The present data support a partial BDZ-bs mediation of the anxiolytic-like and anticonvulsant effects of EA of P. sabulosa and its main isolated constituents, DST and STY.

Extensive evidence indicates the influence of the cholinergic system on emotional processing. Pre... more Extensive evidence indicates the influence of the cholinergic system on emotional processing. Previous findings provided new insights into the underlying mechanisms of long-term anxiety, showing that rats injected with a single systemic dose of pilocarpine—a muscarinic receptor (mAChR) agonist—displayed persistent anxiogenic-like responses when evaluated in different behavioral tests and time-points (24 h up to 3 months later). Herein, we investigated whether the pilocarpine-induced long-term anxiogenesis modulates the HPA axis function and the putative involvement of NMDA receptors (NMDARs) following mAChRs activation. Accordingly, adult male Wistar rats presented anxiogenic-like behavior in the elevated plus-maze (EPM) after 24 h or 1 month of pilocarpine injection (150 mg/kg, i.p.). In these animals, mAChR activation disrupted HPA axis function inducing a long-term increase of corticosterone release associated with a reduced expression of hippocampal GRs, as well as consistently decreased NMDAR subunits expression. Furthermore, in another group of rats injected with memantine–an NMDARs antagonist (4 mg/kg, i.p.)–prior to pilocarpine, we found inhibition of anxiogenic-like behaviors in the EPM but no further alterations in the pilocarpine-induced NMDARs downregulation. Our data provide evidence that behavioral anxiogenesis induced by mAChR activation effectively yields short-and long-term alterations in hippocampal NMDARs expression associated with impairment of hippocampal inhibitory regulation of HPA axis activity. This is a novel mechanism associated with anxiety-like responses in rats, which comprise a putative target to future transla-tional studies.

While anxiety disorders are the brain disorders with the highest prevalence and constitute a majo... more While anxiety disorders are the brain disorders with the highest prevalence and constitute a major burden for society, a considerable number of affected people are still treated insufficiently. Thus, in an attempt to identify potential new anxiolytic drug targets, neuropeptides have gained considerable attention in recent years. Compared to classical neurotransmitters they often have a regionally restricted distribution and may bind to several distinct receptor subtypes. Neuropeptide Y (NPY) is a highly conserved neuropeptide that is specifically concentrated in limbic brain areas and signals via at least 5 different G-protein-coupled receptors. It is involved in a variety of physiological processes including the modulation of emotional-affective behaviors. An anxiolytic and stress-reducing property of NPY is supported by many preclinical studies. Whether NPY may also interact with processing of learned fear and fear extinction is comparatively unknown. However, this has considerable relevance since pathological, inappropriate and generalized fear expression and impaired fear extinction are hallmarks of human post-traumatic stress disorder and a major reason for its treatment-resistance. Recent evidence from different laboratories emphasizes a fearreducing role of NPY, predominantly mediated by exogenous NPY acting on Y1 receptors. Since a reduction of fear expression was also observed in Y1 receptor knockout mice, other Y receptors may be equally important. By acting on Y2 receptors, NPY promotes fear extinction and generates a long-term suppression of fear, two important preconditions that could support cognitive behavioral therapies in human patients. A similar effect has been demonstrated for the closely related pancreatic polypeptide (PP) when acting on Y4 receptors. Preliminary evidence suggests that NPY modulates fear in particular by activation of Y1 and Y2 receptors in the basolateral and central amygdala, respectively. In the basolateral amygdala, NPY signaling activates inhibitory G protein-coupled inwardly-rectifying potassium channels or suppresses hyperpolarization-induced I(h) currents in a Y1 receptordependent fashion, favoring a general suppression of neuronal activity. A more complex situation has been described for the central extended amygdala, where NPY reduces the frequency of inhibitory and excitatory postsynaptic currents. In particular the inhibition of long-range central amygdala output neurons may result in a Y2 receptor-dependent suppression of fear. The role of NPY in processes of learned fear and fear extinction is, however, only beginning to emerge, and multiple questions regarding the relevance of endogenous NPY and different receptor subtypes remain elusive. Y2 receptors may be of particular interest for future studies, since they are the most prominent Y receptor subtype in the human brain and thus among the most promising therapeutic drug targets when translating preclinical evidence to potential new therapies for human anxiety disorders.

Neuropeptides have an important role in several psychiatric conditions. Among them, neuropeptide ... more Neuropeptides have an important role in several psychiatric conditions. Among them, neuropeptide Y (NPY) seems to be essential to modulate some features of stress-related disorders. Post-traumatic stress disorder (PTSD), characterized by inappropriate fear generalization to safe situations may be modulated by NPY manipulation since this neuropeptide is involved in the promotion of coping with stress. Experimentally, coping strategies have been obtained after exposure in enriched environment (EE) rather than standard one. Thus, in the present study we aimed to assess whether short-term EE situation and NPY-Y1 receptor (Y1r) modulation may affect the extinction of contextual fear conditioning, an experimental approach to PTSD. Here we show that EE-rats have the contextual fear extinction facilitated, and this facilitation was reverted by central infusion of BIBO3304, a nonpeptide Y1r antagonist. In addition, protein analysis revealed an upregulation of hippocampal Y1r in conditioned EE-rats, but no changes were observed in EE-rats that were not conditioned. Our results demonstrated that protective properties of EE on fear extinction can be regulated, at least in part, by activation of NPY-signaling through Y1r within hippocampus, an area that plays a major role in contextual memories. Overall, the activation of Y1r is important to promote better and faster perception of self-location (context), and to reduce fear generalization in rats exposed to EE.

Aims: Piperazinic derivatives have therapeutic potential by acting as analgesic, antidepressant-l... more Aims: Piperazinic derivatives have therapeutic potential by acting as analgesic, antidepressant-like, anticonvulsant and antipsychotic in preclinical studies. In order to develop new drugs to treat mental disorders, we designed and synthesized the 4-(1-phenyl-1H-pyrazol-4-ylmethyl)-piperazine-1-carboxylic acid ethyl ester (PPMP), a new piperazine derivative with putative activities on central nervous system that seems to involve serotonergic system. Materials and methods: In order to investigate the antidepressant-like activity of PPMP, mice were treated acutely and tested in the forced swimming test (FST) and tail suspension test. Pretreatment with the 5-HT synthesis inhibitor p-chlorophenylalanine (PCPA, 100 mg/kg, i.p., 4 days), and the non-selective blocker of catecholamine synthesis α-methyl para-tyrosine (AMPT, 100 mg/kg, i.p.) were used to assay the involvement of serotonergic and catecholaminergic systems. " Ex vivo " monoamine oxidase (MAO) enzymatic assay and quantification of hippocampal level of brain derived neurotrophic factor (BDNF) were carried out. Key findings: PPMP reduced the immobility time in both tests. PCPA or AMPT (100 mg/kg, i.p.) pretreatment blocked the effects of PPMP, thereby suggesting the involvement of serotonergic and catecholaminergic systems in the antidepressant-like effect of PPMP. PPMP did not inhibit the activity of MAO. Moreover, after 14 days of treatment, PPMP 15 mg/kg/day induced antidepressant-like effect and increased hippocampal level of BDNF. None of the treatments in this study altered the locomotor activity in the open field test. Significance: In conclusion, PPMP demonstrates antidepressant-like effect that involve both serotonergic and catecholaminergic systems without inhibition of MAO activity. PPMP administration increased the hippocampal levels of BDNF.

In the current study we showed that oral administration of an aqueous extract of Passiflora quadr... more In the current study we showed that oral administration of an aqueous extract of Passiflora quadrangularis L., Passifloraceae, pericarp results in a significant prolongation of the sleep duration in mice evaluated in the ethyl ether-induced hypnosis test which indicates sedative effects. Apigenin, the main flavonoid of the extract, induced a similar sedative response when applied alone, at a dose equivalent to that found in the extract, suggesting that apigenin is mediating the sedative effects of P. quadrangularis extract. In addition, the sedative effect of apigenin was blocked by pretreatment with the benzodiazepine antagonist flumazenil (1 mg/kg), suggesting an interaction of apigenin with gamma-aminobutyric acid type A (GABA A) receptors. However, apigenin at concentrations 0.1–50 M failed to enhance GABA-induced currents through GABA A receptors (1 2 2S) expressed in Xenopus oocytes. Nevertheless, based on our results, we suggest that the in vivo sedative effect of the P. quadrangularis extract and its main flavonoid apigenin maybe be due to an enhancement of the GABAergic system.

without significant change in plasma NPY. Within 30 min of infusion FAM-labeled NPY was detected ... more without significant change in plasma NPY. Within 30 min of infusion FAM-labeled NPY was detected in multiple regions of the brain. When NPY infusion was given 30 min before or immediately after the exposure to single prolonged stress (SPS) rodent PTSD model, it greatly attenuated, and in many cases prevented, the rise in anxiety, hyperarousal and depressive-like behaviors observed weeks after exposure to the traumatic stress. NPY was able to attenuate development of many SPS-triggered neuroendocrine and molecular impairments. NPY prevented SPS triggered induction of CRH, glucocorticoid receptor (GR) and FKBP5 mRNAs and the reduction of phosphorylated GR in the mediobasal hypothalamus, and the increased expression and phosphorylation of GR in the ventral hippocampus. It also prevented the increased expression of NE-biosynthetic enzymes and their sensitization to a stress reminder and to mild novel stressor. It also inhibited the elevation of CRH in the amygdala and the induction of CRHR1 in the brain noradrenergic system. Moreover, single intranasal infusion of NPY to rats a week after SPS stressors, when PTSD symptoms were already developed was anxiolytic, when tested 2 h, and even more so 2 days later. It also had antidepressive-like properties. These findings provide proof of concept for potential of intranasal NPY for PTSD and comorbid disorders of traumatic stress (supported by grant DM102281 from the US Army). Neuropeptide Y (NPY) has been proposed as a potential target for anxiety treatment by modulating its actions through Y 1 and Y 2 receptors. Indeed, cumulative evidence has shown that NPY modulates corticosterone (CORT) secretion, a key component of anxiety and stress. However, the mechanism of action of NPY on CORT is not completely understood. In particular, acute CORT administration induces an increase in anxiogenic-related behavior in the elevated plus maze (EPM) that parallels with neuronal hypertrophy in the basolateral amygdala (BLA). Whether these CORT effects can be prevented by modulation of NPY receptors has not been studied yet. In the present study, we aimed to investigate the behavioral and neuro-protective effects of the Y 1-like receptor agonist, [Leu 31 Pro 34 ] PYY, the Y 1 receptor antagonist, BIBO3304, the Y 2 receptor agonist PYY3-36, and the Y 2 receptor antagonist, BIIE0246 in CORT-treated rats. While BIIE0246 increased the number of entries in the open arm of the EPM in CORT treated rats, PYY3-36 decreased the number of entries in control animals. Neither [Leu 31 Pro 34 ] PYY nor BIBO3304 produced behavioral modifications in CORT treated or control rats. Furthermore, BIIE0246 reduced the neuronal hypertrophy in the BLA in CORT-treated rats without inducing neuronal modifications in control rats. Thus, these results showed that BIIE0246 reverses the behavioral and neuronal deleterious effects of CORT treatment and suggest that selective antagonism of the Y 2 receptor subtype have a potential use in the treatment of anxiety-related disorders. The encoding of emotional memories may occur inappropriately resulting in pathological conditions such as the Post-Traumatic Stress Disorder. Neuropeptide Y is largely expressed on dorsal hippocampus (DH), the main cerebral area related to memory formation. Here we investigated the role of NPY system in the DH of adult male Wistar rats tested on contextual fear conditioning. Institutional Ethical Committee approved all the procedures (PP798). One week after DH bilateral guide cannula implantation, each animal was tested. Drugs were delivered 5 min before the training session to evaluate the fear memory acquisition (ACQ) and immediately after the training to evaluate memory consolidation (CON). Freezing behavior was reported 3 h after conditioning (short term memory — Test A1) and 24 h later (long term memory — Test A2). Effects of drugs on anxiety-like levels were measured on the elevated plus-maze (EPM). Independent groups were used. Only rats that presented successful bilaterally surgeries were considered. During ACQ and CON Test A1, two-way ANOVA showed no significant differences between groups which presented high freezing behavior. During ACQ and CON Test A2, two-way ANOVA showed significant differences between groups. In both cases Newman–Keuls post hoc test showed that NPY 3 and 10 pmol, LP-NPY 1 pmol (Y1 agonist) groups expressed less freezing compared to other groups. Moreover, this effect was prevented by previous BIBO3304 (Y1 antagonist) administration. On EPM, one-way ANOVA showed no statistical difference for the time spent in the open-arm and enclosed-arms entries. Altogether, our results suggest the NPY infusion into DH may impair aversive memory consolidation through Y1 receptor activation, without interfering neither with anxiety levels or locomotor activity.

Os produtos naturais têm servido de inspiração para o desenvolvimento de vários produtos pela ind... more Os produtos naturais têm servido de inspiração para o desenvolvimento de vários produtos pela indústria farmacêutica local e mundial. O objetivo do presente trabalho foi avaliar a atividade farmacológica preliminar do extrato aquoso das folhas secas de Tynanthus micranthus, usando o teste hipocrático em camundongos, como uma ferramenta para direcionar estudos farmacológicos futuros, bem como avaliar os custos envolvidos na execução deste estudo. A T. micranthus Corr. Méllo ex K. Schum, conhecida popularmente como cipó-cravo, é facilmente encontrada na região Noroeste do Estado do Paraná, Brasil, sendo utilizada pela população como calmante e analgésica. No entanto, existem poucos trabalhos científicos com esta espécie vegetal. O cálculo do custo contábil foi realizado para simular o valor gasto por uma empresa privada na realização destas atividades de Pesquisa e Desenvolvimento. Nossos resultados mostram que além do baixo custo, o teste hipocrático proporciona resultados importantes para a decisão da via de administração, toxicidade aguda, efeitos com altas doses e por diferentes vias, além de fornecer informações sobre a latência para os efeitos observados. Com essas informações e uma análise fitoquímica mais aprofundada, isolando e identificando os compostos majoritários, é possível avaliar na literatura a relação composto x atividade farmacológica direcionando de forma mais assertiva as pesquisas a serem realizadas. De maneira geral, apresentamos dados inéditos da espécie estudada (T. micranthus), mostrando uma estratégia de triagem farmacológica simples e de baixo custo para a pesquisa de plantas medicinais nativas que apresentem informações restritas na literatura e que possam servir para o desenvolvimento de novos produtos farmacêuticos. Palavras-chave: Bignoniaceae; plantas medicinais; teste hipocrático ABSTRACT: Natural products have been an inspiration for developing several pharmaceutical products by the local and world industry. The aim of the present study was to evaluate the preliminar pharmacological activity of the aqueous extract from leaves of Tynanthus micranthus, using the hippocratic test in mice as a tool to guide the pharmacological studies, as well as to estimate the costs involved in this process. T. micranthus Corr. Méllo ex K. Schum, popularly known as cipó-cravo, is easily found in the Northwest region of the State of Paraná, Brazil, being used as tranquilizer and analgesic folk medicine. However, there are just few scientific studies on this plant species. The evaluation of financial costs was performed to simulate the value spent by a private company in the realization of these Research & Development activities. Our results show that the Hippocratic test is a low cost test, and produces important results to take the decision about the route of administration, the acute toxicity, pharmacological effects, giving information about the latency to observe the effects. This information plus a further phytochemical analysis, isolating and identifying the major constituents, besides the evaluation in the literature about the relationship between compounds X pharmacological activities, guiding the research to be done. Overall, In the present study we presented an unpublished pharmacological activity (analgesic) for T. micranthus, showing a strategy of a simple and of low cost pharmacological screening to the research of native medicinal plants that present few information in the literature and that could be useful for the development of new pharmaceutical products.

• NK 1 receptor antagonist's FK888 did not alter emotional responses in CA 1 or LSD. • Infusion o... more • NK 1 receptor antagonist's FK888 did not alter emotional responses in CA 1 or LSD. • Infusion of FK888 into CA 1 inhibits long-term anxiogenic responses induced by PILO. • PILO changes anxiogenic responses modulated by SP-NK 1 receptor signaling in CA 1. a b s t r a c t Recent evidence supports a role for the substance P (SP) in the control of anxiety and epilepsy disorders. Aversive stimuli alter SP levels and SP immunoreactivity in limbic regions, suggesting that changes in SP-NK 1 receptor signaling may modulate the neuronal excitability involved in seizures and anxiogenesis. The involvement of NK 1 receptors of the dorsal hippocampus and lateral septum in the anxiogenic-like effects induced by a single injection of pilocarpine (PILO) was examined in non-convulsive rats evaluated in the elevated plus-maze (EPM). Male Wistar rats were systemically injected with methyl-scopolamine (1 mg/kg) followed 30 min later by saline or PILO (350 mg/kg) and only rats that did not present status epilepticus were used. One month later, vehicle or FK888 (100 pmol) – an NK 1 receptor antagonist – were infused in the dorsal hippocampus or the lateral septum of the rats and then behaviorally evaluated in the EPM. Previous treatment with PILO decreased the time spent in and the frequency of entries in the open arms of the EPM, besides altering risk-assessment behaviors such as the number of unprotected head-dipping, protected stretch-attend postures and the frequency of open-arms end activity, showing thus a long-lasting anxiogenic-like profile. FK888 did not show any effect per se but inhibited the anxiogenic responses induced by PILO when injected into the dorsal hippocampus, but not into the lateral septum. Our data suggest that SP-NK 1 receptor signaling of the dorsal hippocampus is involved in the anxiogenic-like profile induced by PILO in rats evaluated in the EPM test.

S288 P.1.h. Basic and clinical neuroscience − Animal behaviour more effectively in RLA rats than ... more S288 P.1.h. Basic and clinical neuroscience − Animal behaviour more effectively in RLA rats than RHA rats (P < 0.05, two-way ANOVA followed by Bonferroni's post hoc test).

Neuropeptide Y (NPY) is the most abundant peptide in the central nervous system (CNS) and is dens... more Neuropeptide Y (NPY) is the most abundant peptide in the central nervous system (CNS) and is densely localized in the brain regions involved in stress, memory, fear and anxiety. Although previous research supports a role for NPY in the mediation of rodent and human emotional behavior, there is currently a lack of information on the effects of low doses of NPY that could have a potential therapeutic advantage, minimizing side-effects such as cognition impairment or sedation. Herein, we assessed the effects of intracerebroventricular (i.c.v.) administration of low doses of NPY, and of the Y1-agonist Leu31Pro34-NPY (LP-NPY) on contextual fear conditioning (CFC), as they have no effect on unconditioned anxiety-like, locomotor activity and non-emotional memory. NPY (3 pmol) and LP-NPY (1 pmol) inhibited freezing behavior when administered in the acquisition or consolidation stages, indicating a reduction of fear. When injected in the extinction phase, only NPY inhibited freezing behavior on CFC. Pre-treatment with the Y1-antagonist BIBO3304 before NPY and LP-NPY was able to prevent the inhibition of fear responses induced by both NPY agonists. Taken together, our results demonstrate robust fear-inhibiting effects of i.c.v. injection of NPY on contextual fear conditioning in rats, a response that is mediated, at least in part, by the Y1 receptor. Moreover, these treatments were unable to change locomotor activity or to show an anxiolytic-like effect, as evaluated in an open-field and an elevated plus-maze. This specific fear reduction effect may underlie resilience systems in the CNS and has potential therapeutic relevance in PTSD.

h i g h l i g h t s NPY prevented A␤ 1-40 -induced depressive-like responses in mice. NPY prevent... more h i g h l i g h t s NPY prevented A␤ 1-40 -induced depressive-like responses in mice. NPY prevented A␤ 1-40 -induced spatial memory impairments in mice. The blockade of Y2 receptors prevented the protective effects of NPY on A␤ 1-40 -treated mice. NPY blunted A␤ 1-40 -induced lipid peroxidation in the hippocampus and prefrontal cortex. a b s t r a c t Neuropeptide Y (NPY) is a 36-amino acid peptide widely distributed in the central nervous system (CNS) that has been associated with the modulation of several functions including food intake, learning and memory, mood and neuroprotection. There is great interest in understanding the role of NPY in the deleterious effects induced by the central accumulation of amyloid-␤ (A␤) peptides, a pathological hallmark of Alzheimer's disease (AD). Herein, we evaluated the effects of a single intracerebroventricular (i.c.v.) administration of NPY (0.0234 mol/L) 15 min prior to the i.c.v. injection of aggregated A␤ 1-40 peptide (400 pmol/mouse) in behavioral and neurochemical parameters related to oxidative stress in mice. Pretreatment with NPY prevented A␤ 1-40 -induced depressive-like responses and spatial memory impairments evaluated in the tail suspension and object location tasks, respectively. The protective effects of NPY on spatial memory of A␤ 1-40 -treated mice were abolished by the pretreatment with the selective Y2 receptor antagonist BIIE0246. On the other hand, the administration of NPY and A␤ 1-40 did not alter the performance of the animals in the elevated plus-maze and open field arena, indicating lack of effects on anxiety state and locomotor function. Although A␤ 1-40 infusion did not change hippocampal and cortical glutathione peroxidase (GPx) activity and glutathione (GSH) levels, A␤ 1-40 -infused animals showed an increased lipid peroxidation in hippocampus and prefrontal cortex that were blunted by NPY administration. These findings indicate that central administration of NPY prevents A␤ 1-40 -induced depressive-like behavior and spatial memory deficits in mice and that this response is mediated, at least in part, by the activation of Y2 receptors and prevention of oxidative stress.

Ghrelin is a gastric hormone that stimulates growth hormone (GH) secretion and food intake to reg... more Ghrelin is a gastric hormone that stimulates growth hormone (GH) secretion and food intake to regulate energy homeostasis and body weight by binding to its receptor, GH secretagogue receptor (GHSR1a), which is most highly expressed in the pituitary and hy-pothalamus. Nowadays there is considerable evidence showing that the GHSR1a is also expressed in numerous extra-hypothalamic neu-ronal populations and the physiological role of ghrelin is by far wider than considered before including learning and memory, anxiety, depression and neuroprotection. The present review attempts to provide a comprehensive picture of the role of ghrelin in the central nervous system and to highlight recent findings showing its potential as an innovative therapeutic agent in neurodegenerative diseases including Alzheimer's disease and Parkinson's disease.