[Effects of the removal of the epiphysis on the hypnogenic action of hexanal in rats].

After pinealectomy a potentiation of the hypnogenic effect of hexobarbital sodium was observed in rats, which was particularly expressed during night hours. Melatonin (0.1 mg/kg, i.p.) attenuated but not fully eliminate this effect. As suggested pineal compounds have an antihypnogenic activity which can be of a pharmacokinetic and pharmacodynamic origin.