| Popis: |
The major postsynaptic receptor for the inhibitory neurotransmitter γ-aminobutyric acid (GABA) is a complex protein containing a chloride channel and modulatory sites for two classes of drugs, the benzodiazepines (BZ) and anti-convulsants/barbiturates (Olsen, 1982). These GABA receptors are also defined by sensitivity to the agonist muscimol and the antagonist bicuculline (Enna, 1983). Barbiturates and related depressants like pyrazolopyridines that enhance GABA-activated chloride permeability at the tissue and cellular level (Nicoll and colleagues, this volume) also are able to enhance benzodiazepine and GABA receptor binding at the molecular level (Leeb-Lundberg et al., 1980, 1981; Olsen & Snowman, 1982; Wong et al., 1984b). These in vitro barbiturate interactions are dependent on the presence of physiological levels of chloride or other anions able to permeate GABA ion channels, and are blocked by picrotoxin and related chloride channel antagonists, as well as by bicuculline, a GABA receptor antagonist. |
