Effects of various phenothiazines on minimal electroshock seizure threshold and spontaneous motor activity of mice.

The effects of chlorpromazine, promazine, prochlorperazine, trifluoperazine, promethazine and mepazine on minimal electroshock seizure threshold and spontaneous motor activity of mice were investigated. All of the drugs tested produced significant depression of motor activity. Ranked in descending order of potency by this test they are trifluoperazine > chlorpromazine > prochlorperazine > promazine > promethazine > mepazine. Chlorpromazine, promazine, mepazine and promethazine all produced significant decreases in minimal electroshock seizure threshold (MET). Chlorpromazine produced a significant decrease in threshold in oral doses of 9 to 18 mgm./kgm., whereas doses of 4.5 and 27 mgm./kgm. failed to produce significant changes in threshold. Trifluoperazine and prochlorperazine did not produce a significant decrease in MET in the doses tested. The data presented indicate that a minimal electroshock seizure threshold-lowering action is not a necessary property of effective, potent, tranquilizing agents.