Inhibitory effects of GABA on K(+)-evoked Ca2+ influx into rat retinal bipolar cell terminals were studied using calcium imaging methods. Application of high K+ evokes a sustained, reversible increase in [Ca2+]i at bipolar cell terminals, which occurs mainly via dihydropyridine-sensitive (L-type) Ca2+ channels. There are at least two GABA receptor subtypes coexisting at bipolar cell terminals: ...

objective(s) the effect of testosterone on anxiety-like behaviors has been the subject of some studies. there is evidence that testosterone modulates anxiety via gaba (gama aminobutyric acid) and gabaergic system. the involvement of gabac receptors in those effects of testosterone on anxiety-like behaviors of the rats was investigated in the present study. materials and methods a group of rats ...

The -aminobutyric acid type C (GABAC) receptor is structurally related to the GABAA receptors, yet quite distinct physiologically and pharmacologically. Neuroactive steroids are known to be potent and efficacious modulators of the GABAA receptor, but they are less well characterized in their actions on the GABAC receptor. We have examined the actions of neuroactive steroids and analogs on 1 (GA...

Effects of gamma-aminobutyric acid (GABA) on the neuronal membrane of the rat major pelvic ganglia (MPG) were studied using intracellular recording techniques, in vitro. Application of GABA (100 microM) to MPG neurons induced a depolarization (GABAd) associated with a decreased membrane input resistance and a slow hyperpolarization (s-GABAh) associated with an increased membrane input resistanc...

In order to investigate the physiological effects of melatonin receptors in the Xenopus tectum, we have used the fluorescent indicator Fluo-4 AM to monitor calcium dynamics of cells in tectal slices. Bath application of KCl elicited fluorescence increases that were reduced by melatonin. This effect was stronger at the end of the light period than at the end of the dark period. Melatonin increas...

The chemical diversity of agents acting on receptors for g-aminobutyric acid (GABA), the major inhibitory neurotransmitter in the brain, is substantial and increasing. This rich diversity offers both challenges and opportunities for medicinal chemists [1]. GABA produces neuronal inhibition by acting on two major types of receptors: ionotropic receptors that are ligand-gated ion channels (GABAA ...

The inhibitory neurotransmitter, GABA, activates a variety of receptors in all areas of the CNS. Two major subtypes of GABA receptors are well known: (1) GABAA receptors are ligand-gated Cl- channels that consist of a heteromeric mixture of protein subunits forming a pentameric structure, and (2) GABAB receptors couple to Ca2+ and K+ channels via G proteins and second messengers. Here, Graham J...

Microtubule-associated proteins (MAPs) have been identified as binding partners for ionotropic GABAA and GABAC receptors. These interactions suggest a potential role for MAPs in the cytoskeletal anchoring of receptor-ion channels at specific subcellular sites, such as synapses.

BACKGROUND Retinitis pigmentosa (RP) is a progressive retinal degenerative disease that causes deterioration of rod and cone photoreceptors. A well-studied animal model of RP is the transgenic P23H rat, which carries a mutation in the rhodopsin gene. Previously, I reported that blocking retinal GABAC receptors in the P23H rat increases light responsiveness of retinal ganglion cells (RGCs). Beca...