Search results for "GABAergic neuron"
showing 10 items of 24 documents
Characterization and Stage-Dependent Lineage Analysis of Intermediate Progenitors of Cortical GABAergic Interneurons
2021
Intermediate progenitors of both excitatory and inhibitory neurons, which can replenish neurons in the adult brain, were recently identified. However, the generation of intermediate progenitors of GABAergic inhibitory neurons (IPGNs) has not been studied in detail. Here, we characterized the spatiotemporal distribution of IPGNs in mouse cerebral cortex. IPGNs generated neurons during both embryonic and postnatal stages, but the embryonic IPGNs were more proliferative. Our lineage tracing analyses showed that the embryonically proliferating IPGNs tended to localize to the superficial layers rather than the deep cortical layers at 3 weeks after birth. We also found that embryonic IPGNs derive…
Neuron-type specific cannabinoid-mediated G protein signalling in mouse hippocampus
2013
Type 1 cannabinoid receptor (CB1) is expressed in different neuronal populations in the mammalian brain. In particular, CB1 on GABAergic or glutamatergic neurons exerts different functions and display different pharmacological properties in vivo. This suggests the existence of neuron-type specific signalling pathways activated by different subpopulations of CB1. In this study, we analysed CB1 expression, binding and signalling in the hippocampus of conditional mutant mice, bearing CB1 deletion in GABAergic (GABA-CB1-KO mice) or cortical glutamatergic neurons (Glu-CB1-KO mice). Compared to their wild-type littermates, Glu-CB1-KO displayed a small decrease of CB1 mRNA amount, immunoreactivity…
Lack of APP and APLP2 in GABAergic Forebrain Neurons Impairs Synaptic Plasticity and Cognition.
2020
AbstractAmyloid-β precursor protein (APP) is central to the pathogenesis of Alzheimer’s disease, yet its physiological functions remain incompletely understood. Previous studies had indicated important synaptic functions of APP and the closely related homologue APLP2 in excitatory forebrain neurons for spine density, synaptic plasticity, and behavior. Here, we show that APP is also widely expressed in several interneuron subtypes, both in hippocampus and cortex. To address the functional role of APP in inhibitory neurons, we generated mice with a conditional APP/APLP2 double knockout (cDKO) in GABAergic forebrain neurons using DlxCre mice. These DlxCre cDKO mice exhibit cognitive deficits i…
Distribution and Function of Gap Junction Coupling in Cortical GABAergic Neurons.
2013
Although gap junctions have been observed in GABAergic interneurons of several brain regions, this chapter focuses on the distribution and functions of gap junctions and connexins in inhibitory interneurons of the cerebral cortex and hippocampus. Evidence for interconnections mediated by electrical synapses is reported for at least eight cerebral cortex interneuron types, classified on the basis of morphology, electrophysiology and molecular markers. The main differences in the organization of these interneuronal networks are summarized in terms of homologous and heterologous electrical coupling and mutual chemical inhibition. The role of connexin36 (Cx36) in forming neuronal electrical syn…
Circuit Specific Functions of Cannabinoid CB1 Receptor in the Balance of Investigatory Drive and Exploration
2011
Well balanced novelty seeking and exploration are fundamental behaviours for survival and are found to be dysfunctional in several psychiatric disorders. Recent studies suggest that the endocannabinoid (eCB) system is an important control system for investigatory drive. Pharmacological treatment of rodents with cannabinergic drugs results in altered social and object investigation. Interestingly, contradictory results have been obtained, depending on the treatment, drug concentration and experimental conditions. The cannabinoid type 1 (CB1) receptor, a central component of the eCB system, is predominantly found at the synapses of two opposing neuronal populations, i.e. on inhibitory GABAerg…
GABA—from Inhibition to Cognition:Emerging Concepts
2018
Neural functioning and plasticity can be studied on different levels of organization and complexity ranging from the molecular and synaptic level to neural circuitry of whole brain networks. Across neuroscience different methods are being applied to better understand the role of various neurotransmitter systems in the evolution of perception and cognition. GABA is the main inhibitory neurotransmitter in the adult mammalian brain and, depending on the brain region, up to 25% of the total number of cortical neurons are GABAergic interneurons. At the one end of the spectrum, GABAergic neurons have been accurately described with regard to cell morphological, molecular, and electrophysiological…
Resonance properties of GABAergic interneurons in immature GAD67-GFP mouse neocortex.
2014
Subthreshold resonance is a characteristic membrane property of different neuronal classes, is critically involved in the generation of network oscillations, and tunes the integration of synaptic inputs to particular frequency ranges. In order to investigate whether neocortical GABAergic interneurons show resonant behavior already during early postnatal development, we performed whole-cell patch-clamp recordings from visually identified interneurons in supragranular layers of parietal regions in coronal neocortical slices from postnatal day (P) P6-P13 GAD67-GFP knock-in mice. Subthreshold resonance was analyzed by injection of sinusoidal current with varying frequency. About 50% of the inve…
Extended Flight Bouts Require Disinhibition from GABAergic Mushroom Body Neurons
2019
Summary Insect flight is a complex behavior that requires the integration of multiple sensory inputs with flight motor output. Although previous genetic studies identified central brain monoaminergic neurons that modulate Drosophila flight, neuro-modulatory circuits underlying sustained flight bouts remain unexplored. Certain classes of dopaminergic and octopaminergic neurons that project to the mushroom body, a higher integrating center in the insect brain, are known to modify neuronal output based on contextual cues and thereby organismal behavior. This study focuses on how monoaminergic modulation of mushroom body GABAergic output neurons (MBONs) regulates the duration of flight bouts. O…
Effect of depolarizing GABAA-mediated membrane responses on excitability of Cajal-Retzius cells in the immature rat neocortex
2011
In immature neurons activation of ionotropic GABA receptors induces depolarizing membrane responses due to a high intracellular Cl− concentration ([Cl−]i). However, it is difficult to draw conclusions about the functional consequences of subthreshold GABAergic depolarizations, since GABAergic membrane shunting and additional effects on voltage-dependent ion channels or action potential threshold must be considered. To systematically investigate factors that determine the GABAergic effect on neuronal excitability we performed whole cell patch-clamp recordings from Cajal-Retzius cells in immature rat neocortex, using [Cl−]i between 10 and 50 mM. The effect of focal GABA application was quant…
Maternal inflammation has a profound effect on cortical interneuron development in a stage and subtype-specific manner
2018
AbstractSevere infections during pregnancy are one of the major risk factors for cognitive impairment in the offspring. It has been suggested that maternal inflammation leads to dysfunction of cortical GABAergic interneurons that in turn underlies cognitive impairment of the affected offspring. However, the evidence comes largely from studies of adult or mature brains and how the impairment of inhibitory circuits arises upon maternal inflammation is unknown. Here we show that maternal inflammation affects multiple steps of cortical GABAergic interneuron development, i.e., proliferation of precursor cells, migration and positioning of neuroblasts, as well as neuronal maturation. Importantly,…