CHOLINERGIC MECHANISMS AND SEXUAL-BEHAVIOR IN MALE RABBIT

The effects of cholinolytic as well as of cholinomimetic agents on sexual behavior in male rabbits were investigated. Castrated animals, injected with a supramaximal testosterone dose, were used. Scopolamine or methylscopolamine, 0.1 mg/kg, inhibited sexual activity. A dose of 0.02 mg had no effects. The muscarinic receptor-stimulating drug, pilocarpine, completely inhibited sexual activity at doses of 2, 10 and 50 mg/kg. A subeffective dose of methylscopolamine completely antagonized the effects of pilocarpine 2 mg/kg, partly the effect of pilocarpine 10 mg/kg, and not at all the effect of pilocarpine 50 mg/kg. Scopolamine completely antagonized the effects of pilocarpine 2 and 10 mg/kg, and not at all the effects of pilocarpine 50 mg/kg. The peripheral effects of both the receptor-blocking and stimulating agents is important for the effects on sexual behavior, although a central site of action of pilocarpine cannot be ruled out.