Benzodiazepine receptor mediation of the anxiolytic-like effect of (-)-nicotine in mice.

The anxiolytic-like effect of (-)-nicotine (1.9 mumol/kg, IP) on the elevated plus-maze in CD1 mice was blocked by the benzodiazepine receptor antagonist flumazenil (1 and 10 mumol/kg, IP). On the other hand, the cholinergic nicotinic channel blocker mecamylamine (1 to 15 mumol/kg, IP), did not affect the anxiolytic-like properties of diazepam in the same test. These data suggest that the reduction in anxiety induced by (-)-nicotine occurs indirectly via the release of endogenous substances that can activate the benzodiazepine receptor.