Influence of methyldopa on central effects of reserpine

Methyldopa potentiated hypnosis due to hexobarbitone in mice, as did reserpine, chlorpromazine and 5-hydroxytryptamine. Methyldopa antagonized the increase by reserpine of sleep due to hexobarbitone, but enhanced the potentiation by chlorpromazine and 5-hydroxytryptamine of hypnosis due to hexobarbitone. The sedative effect of reserpine in mice and the emetic effect in pigeons were also antagonized by methyldopa. However, the effects of reserpine on convulsions due to leptazol and in causing ptosis were not antagonized by methyldopa. It is suggested that some effects of reserpine (potentiation of hexobarbitone-sleeping time, sedation and emesis) are unrelated to changes in brain amine levels and that methyldopa, with its weak reserpine-like actions, is an antagonist to reserpine.