The effects of gamma-aminobutyric acid (GABA) on the electrophysiological properties of intracardiac neurones were investigated in the intracardiac ganglion plexus in situ and in dissociated neurones from neonatal, juvenile and adult rat hearts. Focal application of GABA evoked a depolarizing, excitatory response in both intact and dissociated intracardiac ganglion neurones. Under voltage clamp...

GABA(C) receptors are the least studied of the three major classes of GABA receptors. The physiological roles of GABA(C) receptors are still being unravelled and the pharmacology of these receptors is being developed. A range of agents has been described that act on GABA(C) receptors with varying degrees of specificity as agonists, partial agonists, antagonists and allosteric modulators. Pharma...

The spinal network coordinating locomotion is comprised of a core of glutamate and glycine interneurons. This network is modulated by several transmitter systems including spinal GABA interneurons. The purpose of this study is to explore the contribution of GABAergic neurons to the regulation of locomotor burst frequency in the lamprey model. Using gabazine, a competitive GABAA antagonist more ...

Vesicular GABA and intraterminal glutamate concentrations are in equilibrium, suggesting inhibitory efficacy may depend on glutamate availability. Two main intraterminal glutamate sources are uptake by neuronal glutamate transporters and glutamine synthesized through the astrocytic glutamate-glutamine cycle. We examined the involvement of the glutamate-glutamine cycle in modulating GABAergic sy...

Endogenous D-serine is a putative dominant co-agonist for the N-methyl-D-aspartate glutamate receptor (NMDAR) in the mammalian forebrain. Although the NMDAR regulates the higher order brain functions by interacting with various neurotransmitter systems, the possible interactions between D-serine and an extra-glutamatergic system largely remain elusive. For the first time, we show in the rat and...

Light-evoked currents in depolarizing and hyperpolarizing bipolar cells (DBCs and HBCs) were recorded under voltage-clamp conditions in living retinal slices of the larval tiger salamander. Responses to illumination at the center of the DBCs' and HBCs' receptive fields were mediated by two postsynaptic currents: DeltaI(C), a glutamate-gated cation current with a reversal potential near 0 mV, an...

Amacrine cells in the vertebrate retina receive glutamatergic input from bipolar cells and make synapses onto bipolar cells, ganglion cells, and other amacrine cells. Recent studies indicate that amacrine cells express metabotropic glutamate receptors (mGluRs) and that signaling within the inner plexiform layer (IPL) of the retina might be modulated by mGluR activity. This study tests the hypot...