Search results for "Aminobutyric acid"
showing 10 items of 156 documents
Laminar distribution and morphology of gamma-aminobutyric acid (GABA)-immunoreactive neurons in the medial and dorsomedial areas of the cerebral cort…
1988
The morphology and laminar distribution of immunolabeled neurons in the medial and dorsomedial telencephalic cortices of the lizard Podarcis hispanica were examined in vibratome sections after preembedding γ-aminobutyric acid (GABA)-immunocytochemistry. In both cortical areas and at all rostrocaudal levels, GABA-immunoreactive neurons were found in all cortical layers, with the largest number (74%) of GABA-positive cells in layer 3. GABA-positive neurons were classified into pyramidlike, vertical-fusiform, multipolar, and horizontal neurons. Cells that could be so classified were counted in each cortical lamina. In the medial cortex, multipolar and horizontal-bipolar cells dominated layer 1…
Cellular Mechanisms of Subplate-Driven and Cholinergic Input-Dependent Network Activity in the Neonatal Rat Somatosensory Cortex
2008
Early coordinated network activity promotes the development of cortical structures. Although these early activity patterns have been recently characterized with respect to their developmental, spatial and dynamic properties, the cellular mechanisms by which specific neuronal populations trigger coordinated activity in the neonatal cerebral cortex are still poorly understood. Here we characterize the cellular and molecular processes leading to generation of network activity during early postnatal development. We show that the somatosensory cortex of newborn rats expresses cholinergic-driven calcium transients which are synchronized within the deeply located subplate. Correspondingly, endogen…
Nrg1 haploinsufficiency alters inhibitory cortical circuits
2021
Neuregulin 1 (NRG1) and its receptor ERBB4 are schizophrenia (SZ) risk genes that control the development of both excitatory and inhibitory cortical circuits. Most studies focused on the characterization ErbB4 deficient mice. However, ErbB4 deletion concurrently perturbs the signaling of Nrg1 and Neuregulin 3 (Nrg3), another ligand expressed in the cortex. In addition, NRG1 polymorphisms linked to SZ locate mainly in non-coding regions and they may partially reduce Nrg1 expression. Here, to study the relevance of Nrg1 partial loss-of-function in cortical circuits we characterized a recently developed haploinsufficient mouse model of Nrg1 (Nrg1tm1Lex). These mice display SZ-like behavioral d…
Coincident glutamatergic depolarizations enhance GABAA receptor-dependent Cl- influx in mature and suppress Cl- efflux in immature neurons.
2021
The impact of GABAergic transmission on neuronal excitability depends on the Cl--gradient across membranes. However, the Cl--fluxes through GABAA receptors alter the intracellular Cl- concentration ([Cl-]i) and in turn attenuate GABAergic responses, a process termed ionic plasticity. Recently it has been shown that coincident glutamatergic inputs significantly affect ionic plasticity. Yet how the [Cl-]i changes depend on the properties of glutamatergic inputs and their spatiotemporal relation to GABAergic stimuli is unknown. To investigate this issue, we used compartmental biophysical models of Cl- dynamics simulating either a simple ball-and-stick topology or a reconstructed CA3 neuron. Th…
Nitric oxide and brain hyperexcitability.
2004
Nitric oxide (NO) is a gaseous messenger involved in atypical forms of intercellular communications, able to exert a strong functional modulation of several neurotransmitter systems. In particular, NO heavily influences the excitatory neurotransmitter glutamate, mainly through NMDA receptors, and the inhibitory neurotransmitter GABA, mainly through GABA A receptors. Due to the involvement of glutamate and GABA in a delicate balance conditioning the functional status of the neural cells, this interaction suggests a role for NO in regulating neuronal excitability and its transition towards hyperexcitability phenomena. This article reviews the main knowledge about the relationships existing be…
Pre- and postsynaptic type-1 cannabinoid receptors control the alterations of glutamate transmission in experimental autoimmune encephalomyelitis
2013
Type-1 cannabinoid receptors (CB1R) are important regulators of the neurodegenerative damage in multiple sclerosis (MS) and in experimental autoimmune encephalomyelitis (EAE). In GABAergic striatal neurons, CB1R stimulation exerts protective effects by limiting inflammation-induced potentiation of glutamate-mediated spontaneous excitatory postsynaptic currents (sEPSCs). Here we show that CB1R located on GABAergic or on glutamatergic neurons are differentially involved in the pre- and postsynaptic alterations of sEPSCs caused by EAE in the striatum. After induction of EAE, mice selectively lacking CB1R on GABAergic neurons (GABA-CB1R-KO) showed exacerbated alterations of sEPSC duration in GA…
The GABAergic System and the Gastrointestinal Physiopathology.
2015
Since the first report about the presence of γ-aminobutyric acid (GABA) within the gastrointestinal (GI) tract, accumulating evidence strongly supports the widespread representation of the GABAergic system in the enteric milieu, underlining its potential multifunctional role in the regulation of GI functions in health and disease. GABA and GABA receptors are widely distributed throughout the GI tract, constituting a complex network likely regulating the diverse GI behaviour patterns, cooperating with other major neurotransmitters and mediators for maintaining GI homeostasis in physiologic and pathologic conditions. GABA is involved in the circuitry of the enteric nervous system, controlling…
Transporter-mediated replacement of extracellular glutamate for GABA in the developing murine neocortex
2013
During early development, cortical neurons migrate from their places of origin to their final destinations where they differentiate and establish synaptic connections. During corticogenesis, radially migrating cells move from deeper zone to the marginal zone, but they do not invade the latter. This "stop" function of the marginal zone is mediated by a number of factors, including glutamate and γ-aminobutyric acid (GABA), two main neurotransmitters in the central nervous system. In the marginal zone, GABA has been shown to be released via GABA transporters (GAT)-2/3, whereas glutamate transporters (EAATs) operate in the uptake mode. In this study, GABAergic postsynaptic currents (GPSCs) were…
The inhibitory neural circuitry as target of antiepileptic drugs.
2001
Impairments and defects in the inhibitory neurotransmission in the CNS can contribute to various seizure disorders, i.e., gamma-aminobutyric acid (GABA) and glycine as the main inhibitory neurotransmitters in the brain play a crucial role in some forms of epilepsy. Recent advances in deciphering the molecular basis of the GABAergic and glycinergic systems has been achieved by means of cloning techniques and gene targeting strategies in animals, contributing to the understanding of drug action. As well, several anticonvulsive substances emerged which target key molecules of the inhibitory systems. Employment of recombinant expression systems, including, but not restricted to the inhibitory c…
GABA transporters control GABAergic neurotransmission in the mouse subplate.
2015
The subplate is a transient layer between the cortical plate and intermediate zone in the developing cortex. Thalamo-cortical axons form temporary synapses on subplate neurons (SPns) before invading the cortical plate. Neuronal activity within the subplate is of critical importance for the development of neocortical circuits and architecture. Although both glutamatergic and GABAergic inputs on SPns were reported, short-term plasticity of GABAergic transmission has not been investigated yet. GABAergic postsynaptic currents (GPSCs) were recorded from SPns in coronal neocortical slices prepared from postnatal day 3-4 mice using whole-cell patch-clamp technique. Evoked GPSCs (eGPSCs) elicited b…