Aging: Effect on ex-vivo benzodiazepine binding after a diazepam injection

Ex vivo ³H]flunitrazepam receptor occupation was determined in the brain of young, mature and old male Fischer 344 rats after a single intravenous injection of a low dose of diazepam. The two benzodiazepine receptor subtypes or conformations (BZ₁ and BZ₂) were differentiated by the displacement of ³H]flunitrazepam specific binding with the triazolopyridazine, CL 218,872. The acute diazepam injection decreased ex vivo ³H]flunitrazepam binding in only the senescent rats. The ³H]flunitrazepam binding at both the BZ₁ and BZ₂ receptor or receptor conformation was significantly reduced in the old rats.