Francesco Ferraguti | Medical University Innsbruck (original) (raw)

Papers by Francesco Ferraguti

Inhibitory Fear Memory Engram in the Mouse Central Lateral Amygdala

Social Science Research Network, 2022

Marco Capogna, a pioneering neuroscientist and true European

European Journal of Neuroscience, Apr 18, 2023

Marco Capogna PhD, Professor of Neuroscience at Aarhus University Faculty of Health, Department o... more Marco Capogna PhD, Professor of Neuroscience at Aarhus University Faculty of Health, Department of Biomedicine, Aarhus, Denmark, died from cancer aged 64 on 2nd December 2022.

Neuroinformatics, Jun 26, 2023

To accurately explore the anatomical organization of neural circuits in the brain, it is crucial ... more To accurately explore the anatomical organization of neural circuits in the brain, it is crucial to map the experimental brain data onto a standardized system of coordinates. Studying 2D histological mouse brain slices remains the standard procedure in many laboratories. Mapping these 2D brain slices is challenging; due to deformations, artifacts, and tilted angles introduced during the standard preparation and slicing process. In addition, analysis of experimental mouse brain slices can be highly dependent on the level of expertise of the human operator. Here we propose a computational tool for Accurate Mouse Brain Image Analysis (AMBIA), to map 2D mouse brain slices on the 3D brain model with minimal human intervention. AMBIA has a modular design that comprises a localization module and a registration module. The localization module is a deep learning-based pipeline that localizes a single 2D slice in the 3D Allen Brain Atlas and generates a corresponding atlas plane. The registration module is built upon the Ardent python package that performs deformable 2D registration between the brain slice to its corresponding atlas. By comparing AMBIA's performance in localization and registration to human ratings, we demonstrate that it performs at a human expert level. AMBIA provides an intuitive and highly efficient way for accurate registration of experimental 2D mouse brain images to 3D digital mouse brain atlas. Our tool provides a graphical user interface and it is designed to be used by researchers with minimal programming knowledge.

JoVE Video Dataset

Journal of Visualized Experiments, Apr 15, 2016

Distribution of glutamic acid decarboxylase messenger RNA-containing nerve cell populations of the male rat brain

PubMed, Sep 1, 1990

The distribution of glutamic acid decarboxylase (GAD) mRNA was investigated throughout the rat br... more The distribution of glutamic acid decarboxylase (GAD) mRNA was investigated throughout the rat brain by means of in situ hybridization. Hybridization was carried out with a 35S-radiolabeled cRNA probe transcribed from a cDNA from cat occipital cortex and cloned in a SP6-T7 promoter-containing vector. Fixed tissue sections were hybridized with 35S GAD probe (0.6 kb length). Signal was detected by means of film or emulsion autoradiography. The autoradiograms were semiquantitatively evaluated by means of computer-assisted image analysis. The results obtained with this evaluation were correlated with the results of the semiquantitative analysis of GAD immunoreactivity performed by Mugnaini and Oertel. Specific labeling was only observed in neuronal cell bodies, whereas no labeling was found over neuropil, glial and endothelial cells. The highest labeling was found in the bulbus olfactorius (internal plexiform and granular layers) and in the caudal magnocellular nucleus of the hypothalamus. Strong labeling was observed in the Purkinje layer of the cerebellar cortex, the interpeduncular nucleus, the interstitial nucleus of Cajal, the nucleus of Darkschewitsch and the suprachiasmatic nucleus. Intermediate or low levels of GAD mRNA were present in various brain nuclei, where gamma-aminobutyric acid (GABA)-containing cell bodies had been observed with other techniques. Interestingly, a low level of GAD mRNA was found in the caudate-putamen and nucleus accumbens, where the vast majority of nerve cells is known to contain GAD immunoreactivity. Only a poor correlation was found between the present semiquantitative measurements of GAD mRNA content and previous analyses of the number of GAD-immunoreactive cell bodies. The present study demonstrates that there exists a differential regional expression of GAD mRNA. The comparison with cell counts performed by immunocytochemistry suggests that some brain areas, such as caudate-putamen and nucleus accumbens, contain a large number of GAD-immunoreactive cell bodies which express a low level of GAD mRNA. The opposite seems to be true for other nuclei, such as the globus pallidus, the zona reticulata of the substantia nigra and the inferior collicle, where few GAD-immunoreactive cell bodies contain high levels of GAD mRNA. In conclusion, the present study gives a low magnification map of GAD mRNA levels in the adult male rat brain. Marked biochemical heterogeneities may be present among GABA neuronal populations based on their expression of GAD mRNA. The comparison between the present in situ hybridization and previous immunocytochemical studies suggests that there may exist at least two populations of GABA neurons in the brain, having high and low levels respectively of both GAD mRNA and GAD enzyme.

Metabotropic Glutamate Receptors in Amygdala Functions

Springer eBooks, 2017

Exactly three decades ago, metabotropic glutamate receptors (mGluRs) were discovered as glutamate... more Exactly three decades ago, metabotropic glutamate receptors (mGluRs) were discovered as glutamate receptors coupled to heterotrimeric G-proteins and able to induce polyphosphoinositide hydrolysis. Since then, eight different mGluRs have been identified, which activate a variety of second messenger systems and trigger complex physiological responses in nearly all brain areas. A participation of mGluRs in amygdala networks was shown to regulate emotional-affective behaviours. In this chapter, I will examine the localization of mGluRs in the amygdaloid complex and how genetic and/or pharmacological manipulation of these receptors affects different amygdala-dependent emotional behaviours including fear learning and extinction. Furthermore, I will discuss the growing literature addressing the influence of mGluRs on affective aspects of pain processing within the nociceptive amygdala. Finally, the potential of drugs acting at mGluRs as novel targets for neuropsychiatric disorders characterized by impaired amygdala functions will be examined.

Aspects of neural plasticity in the central nervous system—I. Computer-assisted image analysis methods

Neurochemistry International, 1990

A morphological and functional characterization of the four-vessel occlusion model of transient (... more A morphological and functional characterization of the four-vessel occlusion model of transient (30 min) forebrain ischemia has been carried out. The rats were classified as fully ischemic when an isoelectric pattern of electroencephalographic activity was present within 5 min of the occlusion of carotid arteries. Otherwise they were considered as partially ischemic rats. The modifications of cerebral blood content during and after the ischemic insult were assessed by a histochemical method which visualizes red blood cells in cerebral vessels. The periods of increase and decrease of red blood cell content were found to correspond to previous reports of post-ischemic hyper- and hypoperfusion. Neuronal damage was assessed by a quantitative analysis of Nissl stained preparations of cingulate cortex, dorsal hippocampus and striatum. The signs of morphological damage were quantified by means of computer-assisted image analysis of Nissl preparations. The highest vulnerability to the ischemic insult was demonstrated in the pyramidal layer of the hippocampal CA1 field and in the lateral striatum. Arterial blood pressure measurements were performed during the ischemic and post-ischemic periods, demonstrating a peak increase of arterial blood pressure within 2 min after carotid artery occlusion, followed by a slow decrease towards basal levels during the ischemic period and a full recovery within 15 min of reperfusion. Ischemic rats were tested in a neurological test battery and in a passive avoidance task. While a full recovery of the relatively simple tasks of the neurological test battery was attained within 14 days of reperfusion, a highly significant impairment of passive avoidance behavior was still present 15 days after the ischemic insult. Finally, a discriminant analysis was applied to separate, on the basis of non-invasive techniques (neurological tests and hot plate), the group of completely ischemic rats from that of partially ischemic rats.

IUPHAR/BPS guide to pharmacology CITE, Apr 26, 2023

Metabotropic glutamate (mGlu) receptors (nomenclature as agreed by the nomenclature as agreed by ... more Metabotropic glutamate (mGlu) receptors (nomenclature as agreed by the nomenclature as agreed by the NC-IUPHAR NC-IUPHAR Subcommittee on Subcommittee on Metabotropic Glutamate Receptors [351] Metabotropic Glutamate Receptors [351]) are a family of G protein-coupled receptors activated by the neurotransmitter glutamate [140]. The mGlu family is composed of eight members (named mGlu1 to mGlu 8) which are divided in three groups based on similarities of agonist pharmacology, primary sequence and G protein coupling to effector: Group-I (mGlu 1 and mGlu 5), Group-II (mGlu 2 and mGlu 3) and Group-III (mGlu 4 , mGlu 6 , mGlu 7 and mGlu 8) (see Further reading). Structurally, mGlu are composed of three juxtaposed domains: a core G protein-activating seventransmembrane domain (TM), common to all GPCRs, is linked via a rigid cysteine-rich domain (CRD) to the Venus Flytrap domain (VFTD), a large bi-lobed extracellular domain where glutamate binds. mGlu form constitutive dimers, cross-linked by a disulfide bridge. The structures of the VFTD of mGlu 1 , mGlu 2 , mGlu 3 , mGlu 5 and mGlu 7 have been solved [200, 275, 268, 403]. The structure of the 7 transmembrane (TM) domains of both mGlu1 and mGlu5 have been solved, and confirm a general helical organisation similar to that of other GPCRs, although the helices appear more compacted [88, 433, 62]. Recent advances in cryo-electron microscopy have provided structures of full-length mGlu receptor homodimers [217, 191] and heterodimers [91]. Studies have revealed the possible formation of heterodimers between either group-I receptors, or within and between group-II and-III receptors [89]. First characterised in transfected cells, co-localisation and specific pharmacological properties suggest the existence of such heterodimers in the brain [270, 440, 145, 283, 259, 218]. Beyond heteromerisation with other mGlu receptor subtypes, increasing evidence suggests mGlu receptors form heteromers and larger order complexes with class A GPCRs (reviewed in [140]). The endogenous ligands of mGlu are L-glutamic acid, L-serine-O-phosphate, N-acetylaspartylglutamate (NAAG) and L-cysteine sulphinic acid. Group-I mGlu receptors may be activated by 3,5-DHPG and (S)-3HPG [30] and antagonised by (S)-hexylhomoibotenic acid [235]. Group-II mGlu receptors may be activated by LY389795 [269], LY379268 [269], eglumegad [354, 434], DCG-IV and (2R,3R)-APDC [355], and antagonised by eGlu [170] and LY307452 [425, 105]. Group-III mGlu receptors may be activated by L-AP4 and (R,S)-4-PPG [130]. An example of an antagonist selective for mGlu receptors is LY341495, which blocks mGlu 2 and mGlu 3 at low nanomolar concentrations, mGlu 8 at high nanomolar concentrations, and mGlu 4 , mGlu 5 , and mGlu 7 in the micromolar range [185]. In addition to orthosteric ligands that directly interact with the glutamate recognition site, allosteric modulators that bind within the TM domain have been described. Negative allosteric modulators are listed separately. The positive allosteric modulators most often act as 'potentiators' of an orthosteric agonist response, without significantly activating the receptor in the absence of agonist. Contents Contents This is a citation summary for Metabotropic glutamate receptors in the Guide to Pharmacology database (GtoPdb). It exists purely as an adjunct to the database to facilitate the recognition of citations to and from the database by citation analyzers. Readers will almost certainly want to visit the relevant sections of the database which are given here under database links. GtoPdb is an expert-driven guide to pharmacological targets and the substances that act on them. GtoPdb is a reference work which is most usefully represented as an on-line database. As in any publication this work should be appropriately cited, and the papers it cites should also be recognized. This document provides a citation for the relevant parts of the database, and also provides a reference list for the research cited by those parts. For further details see [42]. Please note that the database version for the citations given in GtoPdb are to the most recent preceding version in which the family or its subfamilies and targets were substantially changed. The links below are to the current version. If you need to consult the cited version, rather than the most recent version, please contact the GtoPdb curators.

Activation of the extracellular signal-regulated kinase 2 by metabotropic glutamate receptors

European Journal of Neuroscience, Jun 1, 1999

Activation of metabotropic glutamate receptors (mGluRs) leads to modulation of a variety of secon... more Activation of metabotropic glutamate receptors (mGluRs) leads to modulation of a variety of second messenger pathways probably including the mitogen‐activated protein kinase (MAPK) extracellular signal‐regulated protein kinases (ERK). MAPK play a key role in the control of cellular responses to changes in the external environment by regulating transcriptional activity and the phosphorylation state of several cytoplasmic targets. In this study, Chinese hamster ovary (CHO) cells permanently transfected with rat mGluR1a, mGluR2 and mGluR4 were employed as a model to examine the activation of MAPK by glutamate through mGluRs. All three mGluR subtypes rapidly stimulated ERK activation. In particular, mGluR1a and mGluR2 preferentially mediated phosphorylation and activation of ERK2 in a pertussis toxin (PTX)‐sensitive and concentration‐dependent manner. The activation was blocked completely by pretreatment with the antagonist (rs)‐α‐methyl‐4‐carboxyphenylglycine (MCPG) or with the MEK inhibitor PD098059. Furthermore, mGluR1a‐mediated ERK activation was suppressed by the depletion of endogenous protein kinase C (PKC) activity and by the PKC inhibitors staurosporine and calphostin C, but not chelerythrine. When cAMP was elevated in mGluR2‐expressing cells, by forskolin or dibutyryl‐cAMP, slight elevation of ERK activity was observed. However, glutamate‐stimulated ERK activation remained unaffected. In these cells, the phosphatidylinositol 3 kinase (PI3K) inhibitor wortmannin produced a significant, albeit only partial, inhibition of mGluR2‐mediated ERK activation. These findings raise the possibility of a MAPK cascade involvement in glutamate‐dependent neuronal plasticity mediated through stimulation of mGluRs.

Positive allosteric modulation of metabotropic glutamate 4 (mGlu4) receptors enhances spontaneous and evoked absence seizures

Neuropharmacology, Feb 1, 2008

Individual metabotropic glutamate (mGlu) receptor subtypes have been implicated in the pathophysi... more Individual metabotropic glutamate (mGlu) receptor subtypes have been implicated in the pathophysiology of epileptic seizures, and are potential targets for novel antiepileptic drugs. Here, we examined the role of the mGlu4 receptor subtype in absence seizures using as models: (i) WAG/Rij rats, which develop spontaneous absence seizures after 2-3months of age; and (ii) mice treated with pentylentetrazole (PTZ, 30mg/kg, s.c.). Expression of mGlu4 receptors was enhanced in the reticular thalamic nucleus (RTN) of symptomatic WAG/Rij rats as compared with age-matched controls, as assessed by immunoblotting and immunohistochemistry. No changes were found in other regions of WAG/Rij rats including ventrobasal thalamic nuclei, somatosensory cortex, and hippocampus. Electron microscopy and in situ hybridization data suggested that mGlu4 receptors in the RTN are localized on excitatory cortical afferents. Systemic injection of the selective mGlu4 receptor positive allosteric modulator, N-phenyl-7-(hydroxyimino)cyclopropa[b]chromen1a-carboxamide (PHCCC, 10mg/kg, s.c.), substantially enhanced the number of spike-and-wave discharges (SWDs) in WAG/Rij rats. Injection of PHCCC also enhanced absence-like seizures in PTZ-treated mice, whereas it was totally inactive in mGlu4 receptor knockout mice, which were intrinsically resistant to PTZ-induced seizures, as expected. This data supports the hypothesis that activation of mGlu4 receptors participates in the generation of absence seizures which can be exacerbated with the use of a positive allosteric modulator.

Authorea (Authorea), Jan 25, 2023

Genomic structure and transcriptional regulation of metabotropic glutamate receptor 8

Nature Neuroscience, Oct 21, 2019

Learning drives behavioral adaptations necessary for survival. While plasticity of excitatory pro... more Learning drives behavioral adaptations necessary for survival. While plasticity of excitatory projection neurons during associative learning is studied extensively, little is known about the contributions of local interneurons. Using fear conditioning as a model for associative learning, we find that behaviorally relevant, salient stimuli cause learning by tapping into a local microcircuit consisting of precisely connected subtypes of inhibitory interneurons. By employing calcium imaging and optogenetics, we demonstrate that vasoactive intestinal peptide (VIP)-expressing interneurons in the basolateral amygdala are activated by aversive events and provide an instructive disinhibitory signal for associative learning. Notably, VIP interneuron responses are plastic and shift from the instructive to the predictive cue upon memory formation. We describe a novel form of adaptive disinhibitory gating by VIP interneurons that allows to discriminate unexpected, important from irrelevant information, and might be a general dynamic circuit motif to trigger stimulus-specific learning, thereby ensuring appropriate behavioral adaptations to salient events. .

VIP-expressing interneurons in the anterior insular cortex contribute to sensory processing to regulate adaptive behavior

Cell Reports

Inumunolocalization of group I and III mGluRs in hippocampal microcircuits

Neuropharmacology, 2002

Molecular Psychiatry, 2018

Using confocal microscopy, intense mGlu 4 immunoreactivity was observed in the soma and dendrites... more Using confocal microscopy, intense mGlu 4 immunoreactivity was observed in the soma and dendrites of neurons neighboring the intercalated cell clusters in the mouse amygdala, adjacent to mGlu1a-positive GABAergic projection neurons. A moderate staining was also observed within the basolateral complex, and in particular, the lateral amygdala, whereas the central nucleus of the amygdala (CeA) was mostly devoid of specific staining (a, b). Photopharmacology was used to investigate the regulatory role of amygdala mGlu 4 receptors on sensory and emotional behaviors associated with persistent inflammatory pain. To this end, we used a small diffusible photoswitchable positive allosteric modulator of mGlu 4 named optogluram that allows optical control of endogenous mGlu 4 in vivo (c). Ligands and light were directly applied in the amygdala of freely behaving mice through stereotaxically implanted hybrid optic and fluid cannulas (d). Through optical control of mGlu 4 , sensory and emotional behaviors were rapidly and reversibly inhibited, as exemplified here by allodynia (e). BA, basal amygdale; CeA, central amygdala; LA, lateral amygdala; mITCd, medial dorsal intercalated cell cluster; mITCv, medial ventral ITC. For more information on this topic, please refer to the article by Zussy et al. on pages 509-520.

Neuroscience, 2005

Mossy fibre sprouting (MFS) is a phenomenon observed in the epileptic hippocampus. We have studie... more Mossy fibre sprouting (MFS) is a phenomenon observed in the epileptic hippocampus. We have studied MFS, in 7, 14 and 21 day in vitro (DIV) organotypic slice cultures, or in slice cultures treated with pilocarpine (0.5 mM) or pilocarpine and atropine (0.1 mM or 0.5 mM) for 48-72 h at 5 DIV and tested at 21 DIV. Acute application of pilocarpine directly activated hilar neurons and elicited epileptic-like discharges in CA3 pyramids and mossy cells of 5-8 DIV cultures, without causing substantial cell death, as assessed by lactate dehydrogenase measurements. Timm staining revealed increases in MFS in chronic pilocarpine-treated cultures, which was prevented by prior application of atropine. Extracellular synaptic responses were recorded in the granule cell layer and elicited by antidromic mossy fibre stimulation. The GABA A antagonist 6imino-3-(4-methoxyphenyl)-1(6H)-pyridazinebutanoic acid (1 M) induced a greater increase in the coastline bursting index in pilocarpine-treated cultures than in 21 DIV controls. However, there was no significant increase in the frequency of spontaneous or miniature synaptic events recorded in granule cells from pilocarpine-treated cultures. Granule cells were filled with biocytin and morphometric analysis revealed that the length of axon collaterals in the granule and molecular layer was longer in pilocarpine-treated cultures than in 21 DIV controls. Dual recordings between granule cells and between granule and hilar neurons showed that pilocarpine-treated cultures had a larger proportion of monosynaptic and polysynaptic connections. The group II metabotropic glutamate receptor (mGluR) agonist LY354740 (0.5 M) suppressed excitatory but not inhibitory monosynaptic currents. LY354740 also inhibited antidromically evoked action currents in granule cells from pilocarpine-and to a lesser extent in pilocarpine and atropine-treated cultures, suggesting that group II mGluRs can reside along the axon and suppress action potential invasion. We provide direct evidence for the development of functional MFS and suggest a novel, axonal mechanism by which presynaptic group II mGluRs can inhibit selected synapses.

Neuropharmacology, 2011

Eight-month old WAG/Rij rats, which developed spontaneous occurring absence seizures, showed a re... more Eight-month old WAG/Rij rats, which developed spontaneous occurring absence seizures, showed a reduced function of mGlu1 metabotropic glutamate receptors in the thalamus, as assessed by in vivo measurements of DHPG-stimulated polyphosphoinositide hydrolysis, in the presence of the mGlu5 antagonist MPEP as compared to age-matched non-epileptic control rats. These symptomatic 8-month old WAG/Rij rats also showed lower levels of thalamic mGlu1a receptors than age-matched controls and 2-month old (pre-symptomatic) WAG/Rij rats, as detected by immunoblotting. Immunohistochemical and in situ hybridization analysis indicated that the reduced expression of mGlu1 receptors found in symptomatic WAG/Rij rats was confined to an area of the thalamus that excluded the ventroposterolateral nucleus. No mGlu1 receptor mRNA was detected in the reticular thalamic nucleus. Pharmacological manipulation of mGlu1 receptors had a strong impact on absence seizures in WAG/Rij rats. Systemic treatment with the mGlu1 receptor enhancer SYN119, corresponding to compound RO0711401, reduced spontaneous spike and wave discharges spike-wave discharges (SWDs) in epileptic rats. Subcutaneous doses of 10 mg/kg of SYN119 only reduced the incidence of SWDs, whereas higher doses (30 mg/kg) also reduced the mean duration of SWDs. In contrast, treatment with the non-competitive mGlu1 receptor antagonist, JNJ16259685 (2.5 and 5 mg/kg, i.p.) increased the incidence of SWDs. These data suggest that absence epilepsy might be associated with a reduction of mGlu1 receptors in the thalamus, and that compounds that amplify the activity of mGlu1 receptors might be developed as novel anti-absence drugs. This article is part of a Special Issue entitled 'Trends in Neuropharmacology: In Memory of Erminio Costa'.

European Journal of Neuroscience, 2005

Zolpidem is a hypnotic benzodiazepine site agonist with some γ‐aminobutyric acid (GABA)A receptor... more Zolpidem is a hypnotic benzodiazepine site agonist with some γ‐aminobutyric acid (GABA)A receptor subtype selectivity. Here, we have tested the effects of zolpidem on the hippocampus of γ2 subunit (γ2F77I) point mutant mice. Analysis of forebrain GABAA receptor expression with immunocytochemistry, quantitative [3H]muscimol and [35S] t‐butylbicyclophosphorothionate (TBPS) autoradiography, membrane binding with [3H]flunitrazepam and [3H]muscimol, and comparison of miniature inhibitory postsynaptic current (mIPSC) parameters did not reveal any differences between homozygous γ2I77/I77 and γ2F77/F77 mice. However, quantitative immunoblot analysis of γ2I77/I77 hippocampi showed some increased levels of γ2, α1, α4 and δ subunits, suggesting that differences between strains may exist in unassembled subunit levels, but not in assembled receptors. Zolpidem (1 µm) enhanced the decay of mIPSCs in CA1 pyramidal cells of control (C57BL/6J, γ2F77/F77) mice by ∼ 60%, and peak amplitude by ∼ 20% at ...

Molecular psychiatry, Apr 4, 2024

Subtype 5 metabotropic glutamate receptors (mGlu 5 ) are known to play an important role in regul... more Subtype 5 metabotropic glutamate receptors (mGlu 5 ) are known to play an important role in regulating cognitive, social and valence systems. However, it remains largely unknown at which circuits and neuronal types mGlu 5 act to influence these behavioral domains. Altered tissue-or cell-specific expression or function of mGlu 5 has been proposed to contribute to the exacerbation of neuropsychiatric disorders. Here, we examined how these receptors regulate the activity of somatostatin-expressing (SST+) neurons, as well as their influence on behavior and brain rhythmic activity. Loss of mGlu 5 in SST+ neurons elicited excitatory synaptic dysfunction in a region and sex-specific manner together with a range of emotional imbalances including diminished social novelty preference, reduced anxiety-like behavior and decreased freezing during retrieval of fear memories. In addition, the absence of mGlu 5 in SST+ neurons during fear processing impaired theta frequency oscillatory activity in the medial prefrontal cortex and ventral hippocampus. These findings reveal a critical role of mGlu 5 in controlling SST+ neurons excitability necessary for regulating negative emotional states.