The role of serotonergic and cholinergic systems in the aggression-stereotypy complex produced by amphetamine in mice

The aggression--stereotypy complex (ASC) was produced in mice by administration of 15 mg/kg of amphetamine. The elevation of cerebral serotonin level in the mouse brain by administration of L-tryptophan or DL-5-hydroxytryptophan suppressed the aggressiveness without affecting significantly the stereotypy. Serotonin antagonists: methysergide and cyproheptadine, did not potentiate clearly the aggressive component of ASC. Cholinomimetics, pilocarpine and physostigmine, strongly suppressed the aggressive component, while a cholinolytic, scopolamine, evidently potentiated the elements of aggressive behavior. The aggressiveness observed in the ASC in the mouse receiving a large dose of amphetanine is predominantly dependent on the increase of activity of dopaminergic system, but seems to be functionally dependent also on the serotonergic and cholinergic systems.