Nanomolar concentrations of propranolol inhibit GABA-stimulated benzodiazepine binding to rat cerebral cortex.
The influence of propranolol on GABA-stimulated [3H]diazepam binding in the rat cerebral cortex was investigated. Maximum potentiation of GABA-stimulated binding (20.6 +/- 4.5%, P less than 0.05) was observed at 100 microM propranolol, whilst maximum inhibition (32.5 +/- 2.5%, P less than 0.01) was observed at 1 nM propranolol. Low concentrations (1 nM) of (+)-propranolol were observed to be equipotent with (+/-)-propranolol in shifting the dose-response curve of GABA-stimulated [3H]diazepam binding by approximately 1/2 log unit. The phenomenon does not therefore show the stereospecificity observed towards either beta-adrenergic receptors or 5-hydroxytryptamine receptors.
D000818:Animals; D002540:Cerebral Cortex / Q000187:drug effects*; D003975:Diazepam / Q000037:antagonists & inhibitors* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D008297:Male; D011433:Propranolol / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D011955:Receptors, Drug / Q000187:drug effects* / Q000378:metabolism; D011963:Receptors, GABA-A; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology*
D011955:Receptors, Drug; D011963:Receptors, GABA-A; D005680:gamma-Aminobutyric Acid; D011433:Propranolol; D003975:Diazepam