marco atzori | Universidad Autónoma de San Luis Potosí (original) (raw)

Papers by marco atzori

Research paper thumbnail of Nueva teoría sobre la depresión: un equilibrio del ánimo entre el sistema nervioso y el inmunológico, con regulación de la serotonina-quinurenina y el eje hipotálamo-hipófiso-suprarrenal

Biomédica, 2018

La hipótesis sobre las causas de la depresión basada en la acción de la serotonina y del sistema ... more La hipótesis sobre las causas de la depresión basada en la acción de la serotonina y del sistema inmunológico, propone que ciertos tipos de estrés distorsionan la relación entre la actividad del sistema inmunitario innato y la del sistema nervioso central.El estrés causado por una infección o el estrés psicológico excesivo activan receptores de tipo toll, como el TLR-4, el factor de transcripción NF-kB, el inflamasoma NLRP3, así como la secreción de interleucina 1 beta (IL-1β) e interleucina 6 (IL-6); esto causa, en primer lugar, los síntomas generales de enfermedad que aparecen con cualquier infección, pero también los síntomas característicos de la depresión como disforia y anhedonia.Las evidencias indican que, si el estímulo persiste o se repite en las siguientes 24 horas, se activa la enzima indolamina 2,3-dioxigenasa (IDO) de la vía metabólica de la quinurenina, lo cual incrementa la síntesis del ácido quinolínico y reduce la síntesis de serotonina. El ácido quinolínico activa ...

Research paper thumbnail of Hypercholesterolemia associated with erythrocytes morphology assessed by scanning electron microscopy in metabolically unhealthy individuals with normal-weight and obesity

Research paper thumbnail of Differential Synaptic Processing Separates Stationary From Transient Inputs to the Auditory Cortex

nature …, 2001

Sound features are blended together en route to the central nervous system before being discrimin... more Sound features are blended together en route to the central nervous system before being discriminated for further processing by the cortical synaptic network. The mechanisms underlying this synaptic processing, however, are largely unexplored. Intracortical processing of the auditory ...

Research paper thumbnail of Cerebrolysin prevents deficits in social behavior, repetitive conduct, and synaptic inhibition in a rat model of autism

Journal of Neuroscience Research

Autism spectrum disorder (ASD) is a syndrome of diverse neuropsychiatric diseases of growing inci... more Autism spectrum disorder (ASD) is a syndrome of diverse neuropsychiatric diseases of growing incidence characterized by repetitive conduct and impaired social behavior and communication for which effective pharmacological treatment is still unavailable. While the mechanisms and etiology of ASD are still unknown, a consensus is emerging about the synaptic nature of the syndrome, suggesting a possible avenue for pharmacological treatment with synaptogenic compounds. The peptidic mixture cerebrolysin (CBL) has been successfully used during the last three decades in the treatment of stroke and neurodegenerative disease. Animal experiments indicate that at least one possible mechanism of action of CBL is through neuroprotection and/or synaptogenesis. In the present study, we tested the effect of CBL treatment (daily injection of 2.5 mL/Kg i.p. during 15 days) on a rat model of ASD. This was based on the offspring (43 male and 51 female pups) of a pregnant female rat injected with valproic acid (VPA, 600 mg/Kg) at the embryonic day 12.5, which previous work has shown to display extensive behavioral, as well as synaptic impairment. Comparison between saline vs. CBL-injected VPA animals shows that CBL treatment improves behavioral as well as synaptic impairments, measured by behavioral performance (social interaction, Y-maze, plus-maze), maximal response of inhibitory γ-amino butyric acid type A receptor (GABAA R)-mediated synaptic currents, as well as their kinetic properties and adrenergic and muscarinic modulation. We speculate that CBL might be a viable and effective candidate for pharmacological treatment or co-treatment of ASD patients. © 2017 Wiley Periodicals, Inc.

Research paper thumbnail of Interleukin 6 trans-signaling regulates basal synaptic transmission and sensitivity to pentylenetetrazole-induced seizures in mice

Synapse

The pro-inflammatory cytokine interleukin 6 (IL-6) interacts with the central nervous system in a... more The pro-inflammatory cytokine interleukin 6 (IL-6) interacts with the central nervous system in a largely unknown manner. We used a genetically modified mouse strain (GFAP-sgp130Fc, TG) and wild type (WT) mice to determine whether IL-6 trans-signaling contributes to basal properties of synaptic transmission. Postsynaptic currents (PSCs) were studied by patch-clamp recording in cortical layer 5 of a mouse prefrontal cortex brain slice preparation. TG and WT animals displayed differences mainly (but not exclusively) in excitatory synaptic responses. The frequency of both action potential-independent (miniature) and action potential-dependent (spontaneous) excitatory PSCs (EPSCs) were higher for TG vs. WT animals. No differences were observed in inhibitory miniature, spontaneous, or tonic inhibitory currents. The pair pulse ratio (PPR) of electrically evoked inhibitory as well as of excitatory PSCs were also larger in TG animals vs. WT ones, while no changes were detected in electrically evoked excitatory-inhibitory synaptic ratio (eEPSC/eIPSC), nor in the ratio between the amino-propionic acid receptor (AMPAR)-mediated and N-methyl D aspartate-R (NMDAR)-mediated components of eEPSCs (IAMPA /INMDA ). Evoked IPSC rise times were shorter for TG vs. WT animals. We also compared the sensitivity of TG and WT animals to pentylenetetrazole (PTZ)-induced seizures. We found that TG animals were more sensitive to PTZ injections, as they displayed longer and more severe seizures. We conclude that the absence of basal IL-6 trans-signaling contributes to increase the basal excitability of the central nervous system, at the system level as well at the synaptic level, at least in the prefrontal cortex.

Research paper thumbnail of Cl-transporter block enhances GABAergic spontaneous activity in rat hippocampal CA3 cells

Neuroreport, 1994

Chloride-cation Transporter Blockers (CTBs) furosemide and ammonium were used to test the effects... more Chloride-cation Transporter Blockers (CTBs) furosemide and ammonium were used to test the effects of changes in the internal [Cl-] on the spontaneous and miniature GABAergic post-synaptic currents (PSCs) of CA3 pyramidal cells of rat hippocampal slices with the whole-cell patch technique. Application of CTBs in the presence of kynurenic acid raised (65 +/- 21%) the frequency of GABAergic spontaneous PSCs leaving unchanged the miniature frequency, indicating that the increase in synaptic activity was caused by interneurone firing. Partial removal of external chloride yielded the same effect, suggesting that ECl contributes to the resting potential of interneurones. PSC rise times were prolonged and their mean amplitude was lowered by furosemide as well as the response to exogenous muscimol, confirming that furosemide exerts some GABAA receptor antagonism.

Research paper thumbnail of Strata, F. et al. Pacemaker current in dye-coupled hilar interneurons contributes to the generation of giant GABAergic potentials in developing hippocampus. J. Neurosci. 17, 1435-1446

The Journal of Neuroscience : The Official Journal of the Society for Neuroscience

The establishment of synaptic connections and their refinement during development require neural ... more The establishment of synaptic connections and their refinement during development require neural activity. Increasing evidence suggests that spontaneous bursts of neural activity within an immature network are mediated by gamma-aminobutyric acid via a paradoxical excitatory action. Our data show that in the developing hippocampus such synchronous burst activity is generated in the hilar region by transiently coupled cells. These cells have been identified as neuronal elements because they fire action potentials and they are not positive for the glial fibrillary acidic protein staining. Oscillations in hilar cells are "paced" by a hyperpolarization-activated current, with properties of Ih. Coactivated interneurons synchronously release GABA, which via its excitatory action may serve a neurotrophic function during the refinement of hippocampal circuitry.

Research paper thumbnail of Nicotine for psychiatric disease: from nuisance to novel treatment?

Future Medicinal Chemistry, 2015

Research paper thumbnail of A pacemaker current in dye-coupled hilar interneurons contributes to the generation of giant GABAergic potentials in developing hippocampus

The Journal of neuroscience : the official journal of the Society for Neuroscience, Jan 15, 1997

The establishment of synaptic connections and their refinement during development require neural ... more The establishment of synaptic connections and their refinement during development require neural activity. Increasing evidence suggests that spontaneous bursts of neural activity within an immature network are mediated by gamma-aminobutyric acid via a paradoxical excitatory action. Our data show that in the developing hippocampus such synchronous burst activity is generated in the hilar region by transiently coupled cells. These cells have been identified as neuronal elements because they fire action potentials and they are not positive for the glial fibrillary acidic protein staining. Oscillations in hilar cells are "paced" by a hyperpolarization-activated current, with properties of Ih. Coactivated interneurons synchronously release GABA, which via its excitatory action may serve a neurotrophic function during the refinement of hippocampal circuitry.

Research paper thumbnail of Local circuitry in auditory cortex studied by neuron-pair patch-clamp recording

Research paper thumbnail of Abnormal Adrenergic Modulation of GABAergic Synaptic Transmission in a Valproic Acid Animal Model of Autism

Research paper thumbnail of Presynaptic and postsynaptic inhibition of GABAergic synaptic transmission mediated by 5-HT1A and 5-HT2A receptors in layer II/III of auditory cortex

Research paper thumbnail of The effect of repeated simulation of the optic nerve on evoked field potentials in the frog optic tectum

Research paper thumbnail of Synaptic fatigue in the Rana temporaria optic tectum in vitro following repetitive stimulation of the optic nerve

Research paper thumbnail of Mechanisms of Control and Modulation of the GABAergic System in the Rat Hippocampus

Research paper thumbnail of Vagal nerve stimulation prevents stress-induced interleukin-6-dependent cortical hyperexcitability

Research paper thumbnail of Prefrontal cortex, hippocampus, and basolateral amygdala plasticity in a rat model of autism spectrum

Synapse, 2014

We aimed to investigate the effect of prenatal administration of valproic acid (VPA) (500 mg/kg) ... more We aimed to investigate the effect of prenatal administration of valproic acid (VPA) (500 mg/kg) at embryonic day 12.5 on the anatomical properties of the prefrontal cortex, hippocampus, and basolateral amygdala, at three different ages: immediately after weaning (postnatal day 21 [PD21]), prepubertal (PD35), and postpubertal (PD70) ages in a rat model of autistic spectrum disorder. Quantitative analysis of the thickness of the prefrontal cortex revealed a reduced size at all study ages in the cingulate 1 area of the prefrontal cortex and CA1 of the dorsal hippocampus in prenatally exposed animals compared to controls. At the level of the basolateral amygdala, a reduction in the size was observed at PD35 and PD70 in the VPA group. In addition, a reduced thickness was observed in the prelimbic region of the prefrontal cortex in VPA animals at PD35. Interestingly, no differences in cortical thickness were observed between control and VPA animals in the infralimbic region of the prefrontal at any age. Our results suggest that prenatal exposure to VPA differentially alters cortical limbic regions anatomical parameters, with implication in the autistic spectrum disorder.

Research paper thumbnail of Interplay Between Dopamine and Acetylcholine in the Modulation of Attention

Monoaminergic Modulation of Cortical Excitability, 2007

Research paper thumbnail of Pyramidal cells and stratum lacunosum-moleculare interneurons in the CA1 hippocampal region share a GABAergic spontaneous input

Hippocampus, 1996

Patch-clamp technique was used in the CA1 region of the hippocampal rat slice preparation in orde... more Patch-clamp technique was used in the CA1 region of the hippocampal rat slice preparation in order to perform a comparison between synaptic GABAergic spontaneous postsynaptic currents (sPSCs) recorded from pyramidal cells (PCs) of stratum pyramidale (SP) and interneurons of stratum-lacunosum moleculare (SL-M INs). GABAergic sPSCs from PCs and from SL-M INs displayed similar frequency (0.75 +/- 0.26 Hz vs. 0.53 +/- 0.11 Hz, respectively), amplitude (34.6 +/- 5.0 pA vs. 39.6 +/- 4.1 pA), rise-time (2.9 +/- 0.4 ms vs. 3.2 +/- 0.3 ms), and decay-time (31.7 +/- 1.5 vs. 32.3 +/- 2.4). Agonists of receptors for endogenously released transmitters were bath-applied to induce variations in the frequency of sPSCs. Spontaneous PSC frequency increased after carbachol and trans-1-aminocyclopentane-1,3-dicarboxilic acid (t-ACPD), whereas it decreased after 5-hydroxy-tryptamine (5-HT) and baclofen in both classes of cells. Cross-correlation analysis of double-patch recordings (one PC and one SL-M IN) revealed 4.4 times as many coincident events as would be expected at random. The ratio between measured and random coincidences did not vary when the sPSCs frequency was increased. These results suggest that the same class of spontaneously active GABAergic cells impinge both on PCs and on SL-M INs, exerting control over them by varying the level of released GABA.

Research paper thumbnail of Postsynaptic induction of mossy fibre long term depression in developing rat hippocampus

NeuroReport, 1996

The whole cell configuration of the patch clamp technique was used to study the mechanisms of ind... more The whole cell configuration of the patch clamp technique was used to study the mechanisms of induction of long term depression (LTD) occurring at the mossy fibre-CA3 synapse between postnatal (P) day 6 and P13. In control conditions, when two pulses were delivered to the mossy fibres with an interval of 50 ms a potentiation of the EPSC evoked by the second pulse associated with a reduction in the number of failures was observed. Tetanization of the mossy fibres induced LTD of the responses to the first and second stimulus without affecting the paired pulse facilitation. Loading the postsynaptic cell with BAPTA prevented the induction of LTD but did not modify the paired pulse facilitation, suggesting that LTD induction occurs at the postsynaptic site.

Research paper thumbnail of Nueva teoría sobre la depresión: un equilibrio del ánimo entre el sistema nervioso y el inmunológico, con regulación de la serotonina-quinurenina y el eje hipotálamo-hipófiso-suprarrenal

Biomédica, 2018

La hipótesis sobre las causas de la depresión basada en la acción de la serotonina y del sistema ... more La hipótesis sobre las causas de la depresión basada en la acción de la serotonina y del sistema inmunológico, propone que ciertos tipos de estrés distorsionan la relación entre la actividad del sistema inmunitario innato y la del sistema nervioso central.El estrés causado por una infección o el estrés psicológico excesivo activan receptores de tipo toll, como el TLR-4, el factor de transcripción NF-kB, el inflamasoma NLRP3, así como la secreción de interleucina 1 beta (IL-1β) e interleucina 6 (IL-6); esto causa, en primer lugar, los síntomas generales de enfermedad que aparecen con cualquier infección, pero también los síntomas característicos de la depresión como disforia y anhedonia.Las evidencias indican que, si el estímulo persiste o se repite en las siguientes 24 horas, se activa la enzima indolamina 2,3-dioxigenasa (IDO) de la vía metabólica de la quinurenina, lo cual incrementa la síntesis del ácido quinolínico y reduce la síntesis de serotonina. El ácido quinolínico activa ...

Research paper thumbnail of Hypercholesterolemia associated with erythrocytes morphology assessed by scanning electron microscopy in metabolically unhealthy individuals with normal-weight and obesity

Research paper thumbnail of Differential Synaptic Processing Separates Stationary From Transient Inputs to the Auditory Cortex

nature …, 2001

Sound features are blended together en route to the central nervous system before being discrimin... more Sound features are blended together en route to the central nervous system before being discriminated for further processing by the cortical synaptic network. The mechanisms underlying this synaptic processing, however, are largely unexplored. Intracortical processing of the auditory ...

Research paper thumbnail of Cerebrolysin prevents deficits in social behavior, repetitive conduct, and synaptic inhibition in a rat model of autism

Journal of Neuroscience Research

Autism spectrum disorder (ASD) is a syndrome of diverse neuropsychiatric diseases of growing inci... more Autism spectrum disorder (ASD) is a syndrome of diverse neuropsychiatric diseases of growing incidence characterized by repetitive conduct and impaired social behavior and communication for which effective pharmacological treatment is still unavailable. While the mechanisms and etiology of ASD are still unknown, a consensus is emerging about the synaptic nature of the syndrome, suggesting a possible avenue for pharmacological treatment with synaptogenic compounds. The peptidic mixture cerebrolysin (CBL) has been successfully used during the last three decades in the treatment of stroke and neurodegenerative disease. Animal experiments indicate that at least one possible mechanism of action of CBL is through neuroprotection and/or synaptogenesis. In the present study, we tested the effect of CBL treatment (daily injection of 2.5 mL/Kg i.p. during 15 days) on a rat model of ASD. This was based on the offspring (43 male and 51 female pups) of a pregnant female rat injected with valproic acid (VPA, 600 mg/Kg) at the embryonic day 12.5, which previous work has shown to display extensive behavioral, as well as synaptic impairment. Comparison between saline vs. CBL-injected VPA animals shows that CBL treatment improves behavioral as well as synaptic impairments, measured by behavioral performance (social interaction, Y-maze, plus-maze), maximal response of inhibitory γ-amino butyric acid type A receptor (GABAA R)-mediated synaptic currents, as well as their kinetic properties and adrenergic and muscarinic modulation. We speculate that CBL might be a viable and effective candidate for pharmacological treatment or co-treatment of ASD patients. © 2017 Wiley Periodicals, Inc.

Research paper thumbnail of Interleukin 6 trans-signaling regulates basal synaptic transmission and sensitivity to pentylenetetrazole-induced seizures in mice

Synapse

The pro-inflammatory cytokine interleukin 6 (IL-6) interacts with the central nervous system in a... more The pro-inflammatory cytokine interleukin 6 (IL-6) interacts with the central nervous system in a largely unknown manner. We used a genetically modified mouse strain (GFAP-sgp130Fc, TG) and wild type (WT) mice to determine whether IL-6 trans-signaling contributes to basal properties of synaptic transmission. Postsynaptic currents (PSCs) were studied by patch-clamp recording in cortical layer 5 of a mouse prefrontal cortex brain slice preparation. TG and WT animals displayed differences mainly (but not exclusively) in excitatory synaptic responses. The frequency of both action potential-independent (miniature) and action potential-dependent (spontaneous) excitatory PSCs (EPSCs) were higher for TG vs. WT animals. No differences were observed in inhibitory miniature, spontaneous, or tonic inhibitory currents. The pair pulse ratio (PPR) of electrically evoked inhibitory as well as of excitatory PSCs were also larger in TG animals vs. WT ones, while no changes were detected in electrically evoked excitatory-inhibitory synaptic ratio (eEPSC/eIPSC), nor in the ratio between the amino-propionic acid receptor (AMPAR)-mediated and N-methyl D aspartate-R (NMDAR)-mediated components of eEPSCs (IAMPA /INMDA ). Evoked IPSC rise times were shorter for TG vs. WT animals. We also compared the sensitivity of TG and WT animals to pentylenetetrazole (PTZ)-induced seizures. We found that TG animals were more sensitive to PTZ injections, as they displayed longer and more severe seizures. We conclude that the absence of basal IL-6 trans-signaling contributes to increase the basal excitability of the central nervous system, at the system level as well at the synaptic level, at least in the prefrontal cortex.

Research paper thumbnail of Cl-transporter block enhances GABAergic spontaneous activity in rat hippocampal CA3 cells

Neuroreport, 1994

Chloride-cation Transporter Blockers (CTBs) furosemide and ammonium were used to test the effects... more Chloride-cation Transporter Blockers (CTBs) furosemide and ammonium were used to test the effects of changes in the internal [Cl-] on the spontaneous and miniature GABAergic post-synaptic currents (PSCs) of CA3 pyramidal cells of rat hippocampal slices with the whole-cell patch technique. Application of CTBs in the presence of kynurenic acid raised (65 +/- 21%) the frequency of GABAergic spontaneous PSCs leaving unchanged the miniature frequency, indicating that the increase in synaptic activity was caused by interneurone firing. Partial removal of external chloride yielded the same effect, suggesting that ECl contributes to the resting potential of interneurones. PSC rise times were prolonged and their mean amplitude was lowered by furosemide as well as the response to exogenous muscimol, confirming that furosemide exerts some GABAA receptor antagonism.

Research paper thumbnail of Strata, F. et al. Pacemaker current in dye-coupled hilar interneurons contributes to the generation of giant GABAergic potentials in developing hippocampus. J. Neurosci. 17, 1435-1446

The Journal of Neuroscience : The Official Journal of the Society for Neuroscience

The establishment of synaptic connections and their refinement during development require neural ... more The establishment of synaptic connections and their refinement during development require neural activity. Increasing evidence suggests that spontaneous bursts of neural activity within an immature network are mediated by gamma-aminobutyric acid via a paradoxical excitatory action. Our data show that in the developing hippocampus such synchronous burst activity is generated in the hilar region by transiently coupled cells. These cells have been identified as neuronal elements because they fire action potentials and they are not positive for the glial fibrillary acidic protein staining. Oscillations in hilar cells are "paced" by a hyperpolarization-activated current, with properties of Ih. Coactivated interneurons synchronously release GABA, which via its excitatory action may serve a neurotrophic function during the refinement of hippocampal circuitry.

Research paper thumbnail of Nicotine for psychiatric disease: from nuisance to novel treatment?

Future Medicinal Chemistry, 2015

Research paper thumbnail of A pacemaker current in dye-coupled hilar interneurons contributes to the generation of giant GABAergic potentials in developing hippocampus

The Journal of neuroscience : the official journal of the Society for Neuroscience, Jan 15, 1997

The establishment of synaptic connections and their refinement during development require neural ... more The establishment of synaptic connections and their refinement during development require neural activity. Increasing evidence suggests that spontaneous bursts of neural activity within an immature network are mediated by gamma-aminobutyric acid via a paradoxical excitatory action. Our data show that in the developing hippocampus such synchronous burst activity is generated in the hilar region by transiently coupled cells. These cells have been identified as neuronal elements because they fire action potentials and they are not positive for the glial fibrillary acidic protein staining. Oscillations in hilar cells are "paced" by a hyperpolarization-activated current, with properties of Ih. Coactivated interneurons synchronously release GABA, which via its excitatory action may serve a neurotrophic function during the refinement of hippocampal circuitry.

Research paper thumbnail of Local circuitry in auditory cortex studied by neuron-pair patch-clamp recording

Research paper thumbnail of Abnormal Adrenergic Modulation of GABAergic Synaptic Transmission in a Valproic Acid Animal Model of Autism

Research paper thumbnail of Presynaptic and postsynaptic inhibition of GABAergic synaptic transmission mediated by 5-HT1A and 5-HT2A receptors in layer II/III of auditory cortex

Research paper thumbnail of The effect of repeated simulation of the optic nerve on evoked field potentials in the frog optic tectum

Research paper thumbnail of Synaptic fatigue in the Rana temporaria optic tectum in vitro following repetitive stimulation of the optic nerve

Research paper thumbnail of Mechanisms of Control and Modulation of the GABAergic System in the Rat Hippocampus

Research paper thumbnail of Vagal nerve stimulation prevents stress-induced interleukin-6-dependent cortical hyperexcitability

Research paper thumbnail of Prefrontal cortex, hippocampus, and basolateral amygdala plasticity in a rat model of autism spectrum

Synapse, 2014

We aimed to investigate the effect of prenatal administration of valproic acid (VPA) (500 mg/kg) ... more We aimed to investigate the effect of prenatal administration of valproic acid (VPA) (500 mg/kg) at embryonic day 12.5 on the anatomical properties of the prefrontal cortex, hippocampus, and basolateral amygdala, at three different ages: immediately after weaning (postnatal day 21 [PD21]), prepubertal (PD35), and postpubertal (PD70) ages in a rat model of autistic spectrum disorder. Quantitative analysis of the thickness of the prefrontal cortex revealed a reduced size at all study ages in the cingulate 1 area of the prefrontal cortex and CA1 of the dorsal hippocampus in prenatally exposed animals compared to controls. At the level of the basolateral amygdala, a reduction in the size was observed at PD35 and PD70 in the VPA group. In addition, a reduced thickness was observed in the prelimbic region of the prefrontal cortex in VPA animals at PD35. Interestingly, no differences in cortical thickness were observed between control and VPA animals in the infralimbic region of the prefrontal at any age. Our results suggest that prenatal exposure to VPA differentially alters cortical limbic regions anatomical parameters, with implication in the autistic spectrum disorder.

Research paper thumbnail of Interplay Between Dopamine and Acetylcholine in the Modulation of Attention

Monoaminergic Modulation of Cortical Excitability, 2007

Research paper thumbnail of Pyramidal cells and stratum lacunosum-moleculare interneurons in the CA1 hippocampal region share a GABAergic spontaneous input

Hippocampus, 1996

Patch-clamp technique was used in the CA1 region of the hippocampal rat slice preparation in orde... more Patch-clamp technique was used in the CA1 region of the hippocampal rat slice preparation in order to perform a comparison between synaptic GABAergic spontaneous postsynaptic currents (sPSCs) recorded from pyramidal cells (PCs) of stratum pyramidale (SP) and interneurons of stratum-lacunosum moleculare (SL-M INs). GABAergic sPSCs from PCs and from SL-M INs displayed similar frequency (0.75 +/- 0.26 Hz vs. 0.53 +/- 0.11 Hz, respectively), amplitude (34.6 +/- 5.0 pA vs. 39.6 +/- 4.1 pA), rise-time (2.9 +/- 0.4 ms vs. 3.2 +/- 0.3 ms), and decay-time (31.7 +/- 1.5 vs. 32.3 +/- 2.4). Agonists of receptors for endogenously released transmitters were bath-applied to induce variations in the frequency of sPSCs. Spontaneous PSC frequency increased after carbachol and trans-1-aminocyclopentane-1,3-dicarboxilic acid (t-ACPD), whereas it decreased after 5-hydroxy-tryptamine (5-HT) and baclofen in both classes of cells. Cross-correlation analysis of double-patch recordings (one PC and one SL-M IN) revealed 4.4 times as many coincident events as would be expected at random. The ratio between measured and random coincidences did not vary when the sPSCs frequency was increased. These results suggest that the same class of spontaneously active GABAergic cells impinge both on PCs and on SL-M INs, exerting control over them by varying the level of released GABA.

Research paper thumbnail of Postsynaptic induction of mossy fibre long term depression in developing rat hippocampus

NeuroReport, 1996

The whole cell configuration of the patch clamp technique was used to study the mechanisms of ind... more The whole cell configuration of the patch clamp technique was used to study the mechanisms of induction of long term depression (LTD) occurring at the mossy fibre-CA3 synapse between postnatal (P) day 6 and P13. In control conditions, when two pulses were delivered to the mossy fibres with an interval of 50 ms a potentiation of the EPSC evoked by the second pulse associated with a reduction in the number of failures was observed. Tetanization of the mossy fibres induced LTD of the responses to the first and second stimulus without affecting the paired pulse facilitation. Loading the postsynaptic cell with BAPTA prevented the induction of LTD but did not modify the paired pulse facilitation, suggesting that LTD induction occurs at the postsynaptic site.