Cocaine: peak time of action on isolation-induced fighting.

Cocaine (35 mg/kg i.p.) produced a peak increase in fighting duration in isolated male ICR mice at 30 minutes. However, the crest of this peak ranged from 15--45 minutes. During the offset period (45--120 min.), fight duration remained elevated, but at a lower level. At 240 and 360 minutes, fighting had essentially returned to control levels. The results coincide with peak effects reported by others for locomotor activity, stereotypy, and other cocaine-induced behaviors in animals but later than physiological and subjective parameters measured in human volunteers (cocaine addicts) after intravenous and intranasal administration of the drug.