[Delay in formation of phenamine tolerance after epiphysectomy in rats]

Amphetamine-induced stereotyped behavior is a nonsteady oscillatory process with minute fluctuations rate of head turnings. After acute amphetamine stereotypy have lower amplitude and limited rhythmicity in pinealectomized rats as compared with intact animals. Pinealectomy also delayed tolerance after chronic administration of amphetamine (5 mg/kg/day, 14 days) without usual decrease number of short period (2-3 min) fluctuations in time course of stereotypy.