GABAergic

About: GABAergic is a research topic. Over the lifetime, 9595 publications have been published within this topic receiving 473568 citations.

Target-selective GABAergic control of entorhinal cortex output

Abstract: The medial entorhinal cortex (MEC) is a major center for spatial navigation and memory. We found that cannabinoid type 1 receptor-expressing GABAergic basket cells selectively innervated principal cells in layer II of the rat MEC that projected outside the hippocampus but avoided neighboring cells that give rise to the perforant pathway to the dentate gyrus. These results indicate that the organization of GABAergic microcircuits reflects the long-distance axonal targets of principal neurons.

GABAergic and glutamatergic efferents of the mouse ventral tegmental area

Abstract: The role of dopaminergic (DA) projections from the ventral tegmental area (VTA) in appetitive and rewarding behavior has been widely studied, but the VTA also has documented DA-independent functions. Several drugs of abuse, act on VTA GABAergic neurons, and most studies have focused on local inhibitory connections. Relatively little is known about VTA GABA projection neurons and their connections to brain sites outside the VTA. This study employed viral-vector-mediated cell-type-specific anterograde tracing, classical retrograde tracing, and immunohistochemistry to characterize VTA GABA efferents throughout the brain. We found that VTA GABA neurons project widely to forebrain and brainstem targets, including the ventral pallidum, lateral and magnocellular preoptic nuclei, lateral hypothalamus, and lateral habenula. Minor projections also go to central amygdala, mediodorsal thalamus, dorsal raphe, and deep mesencephalic nuclei, and sparse projections go to prefrontal cortical regions and to nucleus accumbens shell and core. These projections differ from the major VTA DA target regions. Retrograde tracing studies confirmed results from the anterograde experiments and differences in projections from VTA subnuclei. Retrogradely labeled GABA neurons were not numerous, and most non-tyrosine hydroxylase/retrogradely labeled cells lacked GABAergic markers. Many non-TH/retrogradely labeled cells projecting to several areas expressed VGluT2. VTA GABA and glutamate neurons project throughout the brain, most prominently to regions with reciprocal connections to the VTA. These data indicate that VTA GABA and glutamate neurons may have more DA-independent functions than previously recognized.

Reduced GABA Concentration in Attention-Deficit/Hyperactivity Disorder

Abstract: Context Attention-deficit/hyperactivity disorder (ADHD) is a developmental disorder characterized by a deficit in behavioral inhibition. Recent evidence also suggests a deficit in cortical inhibition via the GABA (γ-aminobutyric acid)–ergic system. Objective To investigate the GABAergic component of ADHD using magnetic resonance spectroscopy. Design Cross-sectional study. Setting Participants were recruited through local schools, local pediatric and other community clinics, and through advertisement in regional publications. Magnetic resonance spectroscopy was performed within the research institute. Participants Children (age range, 8-12 years) in a typically developing control group vs a group with ADHD were compared. Main Outcome Measures J-difference–edited magnetic resonance spectroscopy at 3 T was used to measure GABA concentration in a volume that included primary somatosensory and motor cortices. Results GABA concentration is reduced in children with ADHD compared with typically developing control subjects. Conclusion Our finding of reduced GABA concentration in ADHD is concordant with recently reported deficits in short intracortical inhibition in ADHD and suggests a GABAergic deficit in ADHD.

Physiological, neurochemical and morphological properties of a subgroup of GABAergic spinal lamina II neurones identified by expression of green fluorescent protein in mice

Abstract: The processing of sensory, including nociceptive, information in spinal dorsal horn is critically modulated by spinal GABAergic neurones. For example, blockade of spinal GABAA receptors leads to pain evoked by normally innocuous tactile stimulation (tactile allodynia) in rats. GABAergic dorsal horn neurones have been classified neurochemically and morphologically, but little is known about their physiological properties. We used a transgenic mouse strain coexpressing enhanced green fluorescent protein (EGFP) and the GABA-synthesizing enzyme GAD67 to investigate the properties of a subgroup of GABAergic neurones. Immunohistochemistry showed that EGFP-expressing neurones accounted for about one-third of the GABAergic neurones in lamina II of the spinal dorsal horn. They constituted a neurochemically rather heterogeneous group where 27% of the neurones coexpressed glycine, 23% coexpressed parvalbumin and 14% coexpressed neuronal nitric oxide synthase (nNOS). We found almost no expression of protein kinase Cγ (PKCγ) in EGFP-labelled neurones but a high costaining with PKCβII (78%). The whole-cell patch-clamp technique was used to intracellularly label and physiologically characterize EGFP- and non-EGFP-expressing lamina II neurones in spinal cord slices. Sixty-two per cent of the EGFP-labelled neurones were islet cells while the morphology of non-EGFP-labelled neurones was more variable. When stimulated by rectangular current injections, EGFP-expressing neurones typically exhibited an initial bursting firing pattern while non-EGFP-expressing neurones were either of the gap or the delayed firing type. EGFP-expressing neurones received a greater proportion of monosynaptic input from the dorsal root, especially from primary afferent C-fibres. In conclusion, EGFP expression defined a substantial but, with respect to the measured parameters, rather inhomogeneous subgroup of GABAergic neurones in spinal lamina II. These results provide a base to elucidate the functional roles of this subgroup of GABAergic lamina II neurones, e.g. for nociception.