A particular characteristic of the neonatal hippocampus is the presence of spontaneous network-driven oscillatory events, the so-called giant depolarizing potentials (GDPs). GDPs depend on the interplay between GABA and glutamate. Early in development, GABA, acting on GABAA receptors, depolarizes neuronal membranes via a Cl- efflux. Glutamate, via AMPA receptors, generates a positive feedback n...

The mechanism through which kainate receptors downregulate the release of GABA in the hippocampus is not known. We have found that the action of kainate on the hippocampal inhibitory postsynaptic current (IPSC) is mediated by a metabotropic process that is sensitive to Pertussis toxin (PTx) and independent of ion channel current. The downregulation of GABA IPSCs by kainate was also prevented in...

A particular characteristic of the neonatal hippocampus is the presence of spontaneous network-driven oscillatory events, the so-called giant depolarizing potentials (GDPs). GDPs depend on the interplay between GABA and glutamate. Early in development, GABA, acting on GABAA receptors, depolarizes neuronal membranes via a Cl- efflux. Glutamate, via AMPA receptors, generates a positive feedback n...

GABA is the principal inhibitory neurotransmitter in the CNS and acts via GABA(A) and GABA(B) receptors. Recently, a novel form of GABA(A) receptor-mediated inhibition, termed "tonic" inhibition, has been described. Whereas synaptic GABA(A) receptors underlie classical "phasic" GABA(A) receptor-mediated inhibition (inhibitory postsynaptic currents), tonic GABA(A) receptor-mediated inhibition re...

In cerebellar granule cells, delta subunit-containing GABA(A) receptors are found exclusively at extrasynaptic sites, but their subcellular distribution in other brain areas is poorly understood. We examined the anatomical localization and physiological activation of these receptors in adult mouse dentate gyrus granule cells. Immunocytochemistry revealed a high density of delta subunits in the ...

GABA C responses were recorded in cultured cone-driven horizontal cells from the catfish retina using the patch clamp technique. At a holding potential of 2 49 mV, a bicuculline-resistant inward current (I GABA ) was observed when 10 m M GABA was applied. The amplitude of I GABA increased as the extracellular Ca 2 1 ([Ca 2 1 ] o ) was increased. Concentration–response curves of I GABA at 2.5 an...

GABA(C) receptors (GABA(C)Rs) are widely expressed in the mammalian subcortical visual system, particularly in the retina and superior colliculus (SC). GABA(C)Rs are composed of specific rho1-3 subunits the expression of which varies among visual structures. Thus rho1 subunits are most abundant in retina, and their loss eliminates GABA(C)R expression and function. In the SC, rho2 subunit expres...

Functional gamma-aminobutyric acid type B (GABA(B)) receptors are normally only observed upon coexpression of GABA(B1) with GABA(B2) subunits. A C-terminal arginine-based endoplasmic reticulum (ER) retention/retrieval signal, RSRR, prevents escape of unassembled GABA(B1) subunits from the ER and restricts surface expression to correctly assembled heteromeric receptors. The RSRR signal in GABA(B...

The Cys-loop family of ligand-gated ion channels contains both vertebrate and invertebrate members that are activated by GABA (gamma-aminobutyric acid). Many of the residues that are critical for ligand binding have been identified in vertebrate GABA(A) and GABA(C) receptors, and specific interactions between GABA and some of these residues have been determined. In the present paper, I show how...