GABAB receptors are heterodimeric G protein-coupled receptors, which control neuronal excitability by mediating prolonged inhibition. The magnitude of GABAB receptor-mediated inhibition essentially depends on the amount of receptors in the plasma membrane. However, the factors regulating cell surface expression of GABAB receptors are poorly characterized. Cell surface GABAB receptors are consti...

Pre- and postsynaptic adenosine 5'-triphosphate-sensitive potassium (ATP-K+) currents were studied using whole-cell recordings from substantia nigra zona compacta "principal" neurons in midbrain slices. The GABAA and GABAB receptor-mediated synaptic potentials were unaffected by the ATP-K+ channel inhibitor glibenclamide (30 microM) or by the opener diazoxide (500 microM), indicating that ATP-K...

Dopaminergic (DA) neurons in the substantia nigra pars compacta (SNc) are richly innervated by GABAergic neurons. The postsynaptic effects of GABA on SNc DA neurons are mediated by a mixture of GABAA and GABAB receptors. Although activation of GABAA receptors inhibits spike generation, the consequences of GABAB receptor activation are less well characterized. To help fill this gap, perforated p...

[3H]GABA quantitative autoradiography was used to examine the binding kinetics and regional distribution of GABAB receptors in rat brain. The regional distribution was compared to that of GABAA receptors. At 4 degrees C, [3H]GABA binding to GABAB receptors reached equilibrium within 45 min. The association and dissociation rate constants for GABAB binding to outer neocortical layers were 2.87 +...

gamma-Hydroxybutyrate (GHB) has been reported to be a ligand for GABAB receptor(s), although with low or very low affinity (IC50 = 150-796 microM). In addition, several reports argue for a role of GHB via GABAB receptors in both in vivo and in vitro electro-physiological experiments. In the present study, we demonstrate that the inhibition of GHB's conversion into GABA by rat brain membranes bl...

In previous work we have shown that GABAB receptors are required for expression of absence seizures in the lethargic (lh/lh) mouse model; that lh/lh mice have increased numbers of GABAB binding sites compared to nonepileptic littermates (designated +/+); and that the magnitude of the increased number of GABAB receptors in lh/lh mice correlated positively with the frequency of absence seizures. ...

Opioids are intensely addictive, and cessation of their chronic use is associated with a highly aversive withdrawal syndrome. A cellular hallmark of withdrawal is an opioid sensitive protein kinase A-dependent increase in GABA transporter-1 (GAT-1) currents in periaqueductal gray (PAG) neurons. Elevated GAT-1 activity directly increases GABAergic neuronal excitability and synaptic GABA release,...

in the present study, the effect of gaba (γ-aminobutyric acid) receptor agonists and antagonists on morphine-induced antinociception was investigated in formalin test in rats. intraperitoneal (i.p.) injection of different doses of morphine (1, 3, 6 and 9 mg/kg) and intracerebroventricular (i.c.v.) injection of different doses of muscimol (0.5, 1 and 2 g/rat) or baclofen (0.25, 0.5 and 1 g/rat) ...