[The effect of the acute and chronic administration of melatonin on the relearning of rats in a Y maze and their sensitivity to haloperidol].

After acute (10 mg/kg) and chronic (1 mg/kg, 10 days) administration melatonin facilitated parameters of rats relearning in the Y-maze. A simultaneous shortening of latency avoidance reaction was observed. Haloperidol (0.1 mg/kg) against the background of chronic melatonin administration more strongly optimized the animals' relearning. The hormonal action is supposed to depend on its sedative properties.