Cholinergic regulation of sexual behavior in female hamsters.

The effect of cholinergic manipulations on sexual behavior in female hamsters was determined in a series of experiments. The cholinergic receptor antagonist, scopolamine, reduced total lordosis duration following systemic (1 mg/kg) or intraventricular (10 and 20 micrograms bilaterally) administration to ovariectomized hamsters primed with estrogen and progesterone. The inhibitory effect of scopolamine on lordosis occurred within 15 min after either treatment route and persisted at 2 hr after systemic administration. Intraventricular administration of the acetylcholinesterase inhibitor, physostigmine (10 micrograms bilaterally), activated lordosis of short duration in ovariectomized hamsters primed only with estrogen. These results indicate that the cholinergic system plays a facilitative role in the regulation of sexual behavior in female hamsters similar to that demonstrated previously in female rats. The activational effect of cholinergic neurotransmission on female sexual behavior may be a neural mechanism common to a number of mammalian species.