Drug-induced modifications in sexual behavior and open field locomotion of male rats

Abstract

Several drugs were selected for sexual and open field behavioral testing, according to the following criteria: they are known synergists or antagonists of presumptive neurotransmitters; they modify behaviors thought to be related to sexual behavior; or they enjoy a popular reputation as aphrodisiacs in man. The drugs chosen were scopolamine, physostigmine, methamphetamine, cocaine, tranylcypromine, diazepam, cantharidin, and oxytocin. Scopolamine and diazepam disrupted sexual behavior, despite having differential effects on open field locomotion; locomotion was increased by scopolamine and unchanged by diazepam. Cocaine and methamphetamine increased locomotion, and in low doses were the only drugs to accelerate sexual performance. High doses of cocaine also increased locomotion, but had predominantly inhibitory actions on sexual performance. The other drugs were without significant effects on either behavior. The results are interpreted as indicating that activation of adrenergic pathways facilitates the sexual performance of male rats, and that alterations of cholinergic balance are disruptive. Open field activity modifications are not correlated with changes in sexual behavior.