[The influence of melatonin, epiphysectomy and anaprilin on the cataleptogenic effect of haloperidol and its time dynamics].

The acute administration of the pineal hormone melatonin (1 mg/kg) to rats was shown to increase, and the chronic use to decrease intensity of haloperidol-induced catalepsy with the reorganization of the rhythmic pattern of the neuroleptic effect. The direct opposite shifts were observed after pinealectomy or propranolol chronic administration (1 mg/kg). It is suggested that owing to its own adaptive properties the pineal gland can participate in the formation of drug tolerance.