Inhibition is mediated by two classes of ionotropic receptors in the retina, GABA(A) and GABA(C) receptors. We used the GABA transport blocker NO-711 to examine the role of GABA transporters in shaping synaptic responses mediated by these two receptors in the salamander retinal slice preparation. Focal applications (puffs) of GABA onto GABA(C) receptors on bipolar cells terminals or GABA(A) rec...

The potency of GABA is vitally important for its primary role in activating GABA(A) receptors and acting as an inhibitory neurotransmitter. Although numerous laboratories have presented information, directly or indirectly, on GABA potency, it is often difficult to compare across such studies given the inevitable variations in the methods used, the cell types studied, whether native or recombina...

The R- and S-enantiomers of 4-amino-3-hydroxybutanoic acid (GABOB) were full agonists at human recombinant rho1 GABA(C) receptors. Their enantioselectivity (R>S) matched that reported for their agonist actions at GABA(B) receptors, but was the opposite to that reported at GABA(A) receptors (S>R). The corresponding methylphosphinic acid analogues proved to be rho1 GABA(C) receptor antagonists wi...

The paper reviews data concerning the involvement of GABA(A) and GABA(B) receptors in the control of GnRH secretion in anestrous ewes. Generally, GABA influences the GnRH release through GABA(A) and GABA(B) receptors located on perikaria of the GnRH neurons in the preoptic area (MPOA) or through the influence on beta-endorphinergic and catecholaminergic systems activity in MPOA and in ventromed...

Correlated spiking activity and associated Ca(2+) waves in the developing retina are important in determining the connectivity of the visual system. Here, we show that GABA, via GABA(B) receptors, regulates the temporal characteristics of Ca(2+) waves occurring before synapse formation in the embryonic chick retina. Blocking ionotropic GABA receptors did no affect these Ca(2+) transients. Howev...

Ian Martin is Professor of Pharmacology in the School of Life and Health Sciences at the University of Aston, Birmingham B4 7ET, UK. Susan Dunn is a Senior Lecturer in the Department of Pharmacology at the University of Bristol, University Walk, Bristol BS8 1TD, UK. They have common interests in GABAergic transmission in the central nervous system and their research is focused on the structure-...

BACKGROUND gamma-aminobutyric acid (GABA) is an important inhibitory neurotransmitter which mainly mediates its effects on neurons via ionotropic (GABA(A)) and metabotropic (GABA(B)) receptors. GABA(B) receptors are widely expressed in the central and the peripheral nervous system. Although there is evidence for a key function of GABA(B) receptors in the modulation of pain, the relative contrib...

Following the recent discovery that GABA receptors expressed in cell lines are only functional when both GABA and GABA are B B1 B2 expressed, the present study reports on the development of polyclonal antisera specific for carboxyl-terminal portions of the two related GABA receptor components respectively. Western blotting indicated the specificity of affinity-purified antibodies for native or ...

Metabotropic GABA(B) receptors are abundantly expressed at glutamatergic synapses where they control excitability of the synapse. Here we tested the hypothesis that glutamatergic neurotransmission may feed back to regulate GABA(B) receptors. We found that application of glutamate to cultured cortical neurons led to rapid downregulation of GABA(B) receptors via lysosomal degradation. This effect...

GABA(B) receptors are G-protein-coupled receptors mediating the slow onset and prolonged synaptic actions of GABA in the CNS. The recent cloning of two genes, GABA(B1) and GABA(B2), has revealed a novel requirement for GABA(B) receptor signalling. Studies have demonstrated that the two receptor subunits associate as a GABA(B1)/GABA(B2) heterodimer to form a functional GABA(B) receptor. In this ...