Gamma-aminobutyric acid (GABA) concentrations in seminal plasma and washed spermatozoa from normal donors were assessed by a sensitive radioreceptor assay, and were detectable in both fractions. Specific binding of [3H]-muscimol was shown to be dependent on protein concentration, temperature and incubation time. [3H]-muscimol specific binding to human sperm membranes was significantly inhibited...

Dopaminergic axons in the prefrontal cortex synapse with interneurons as well as pyramidal cells. Electrophysiological data suggest that dopamine depolarizes certain gamma-aminobutyric acid (GABA)-containing interneurons in the cortex. We investigated the dopaminergic regulation of extracellular GABA levels in the prefrontal cortex using in vivo microdialysis. Systemic administration of the mix...

The inhibitory neurotransmitter GABA plays a crucial role in anxiety and fear, but its relationship to brain activation during fear reactions is not clear. Previous studies suggest that GABA agonists lead to an attenuation of emotion-processing related BOLD signals in the insula. The aim of this study was to investigate the relationship between GABA concentration and fear-related BOLD responses...

Neuronal voltage-gated N-type (Cav2.2) calcium channels are expressed throughout the nervous system and regulate neurotransmitter release and hence synaptic transmission. They are predominantly modulated via G protein-coupled receptor activated pathways, and the well characterized Gβγ subunits inhibit Cav2.2 currents. Analgesic α-conotoxin Vc1.1, a peptide from predatory marine cone snail venom...

BACKGROUND AND PURPOSE The possible neuroprotective effect of endogenous gamma-aminobutyric acid (GABA) on the irreversible electrophysiological changes induced by in vitro ischemia on striatal neurons was investigated. In particular, the aim of the study was the characterization of the neuroprotective action of 2 antiepileptic drugs increasing GABAergic transmission such as tiagabine, a GABA t...

The influence of GABA agonists and antagonists on analgesic activity of imipramine (IMA, 20 mg/kg, ip) was studied using the hotplate method. Administration of GABAA receptor agonist muscimol (1 mg/kg, ip), GABAB receptor agonist baclofen (3 mg/kg, ip) or GABA-T inhibitor aminooxyacetic acid (25 mg/kg, ip) increased the analgesic effect of IMA. On the other hand pretreatment of GABAA receptor a...

Benzodiazepine (BZ) anxiolytics mediate their clinical effects by enhancing the effect of gamma-aminobutyric acid (GABA) at the GABA-A receptor. Classical BZ full agonists such as diazepam, which maximally enhance the function of GABA-A receptors, are effective anxiolytics but carry unwanted side effects including sedation, dependence and abuse liability, limiting their utility. Although a seco...

Pattern adaptation is very important for visual function, while the mechanisms that mediate pattern adaptation, especially in the dorsal lateral geniculate nucleus (LGNd), are still unclear. Iontophoresis of the antagonists and agonists of GABA receptors were employed to separately investigate the contribution of GABA(A) and GABA(B) receptors to pattern adaptation of LGNd cells. When GABA(A) re...

In this report we describe extracellular recordings made from ON and ON-OFF directionally selective (DS) ganglion cells in the rabbit retina during perfusion with agonists and antagonists to acetylcholine (ACh), glutamate, and gamma-aminobutyric acid (GABA). Nicotinic ACh agonists strongly excited DS ganglion cell in a dose-dependent manner. Dose-response curves showed a wide range of potencies...

Intracellular calcium concentration rises have been reported following activation of GABA(A) receptors in neonatal preparations and attributed to activation of voltage-dependent Ca(2+) channels. However, we show that, in cerebellar interneurons, GABA(A) agonists induce a somatodendritic Ca(2+) rise that persists at least until postnatal day 20 and is not mediated by depolarization-induced Ca(2+...