[THE INFLUENCE OF SCOPOLAMINE AND OTHER CENTRAL STIMULANTS AND DEPRESSANTS ON THE SPONTANEOUS ACTIVITY OF MICE].

The effects of scopolamine,desoxyephedrine,amphetamine,caffeine, morphine,reserpine,chlorpromazine,pontobarbital and meprobamate,and their combined effects on the spontaneous activity of albino mice were determined by the photocell activity cage method. Scopolamine at 0.1 and 0.2 mg/kg intraperitoneally caused a decrease in activi- ty,while 2—4 mg/kg elicited an increase.Desoxyephedrine,amphetamine and morphine alone increased the activity;chlorpromazine and reserpine caused a decrease. In all cases changes in the activity ratio appeared to be in proportion with the dose level.The mice exhibited increased activity under small doses of pentobarbital or meprobamate,but the activity was decreased by larger doses. The increase of activity elicited by scopolamine was exhibited only during the first 20 minutes following the entrance of mice into the cage,after which such an effect was not detectable.The increase of activity following desoxyephedrine,amphe- tamine or morphine was however enhanced progressively throughout a period of 10— 50 minutes,although to various extents.The mice receiving pentobarbital or mepro- bamate exhibited increased activity in the first 10 or 20 minutes,but showed signifi- cantly less activity than the control mice when the observation was prolonged. The combined effects of scopolamine with other central stimulants and depres- sants revealed its dualistic action.The fact that scopolamine in a dose of 4 mg/kg synergized with the stimulating effects of amphetamine,desoxyephedrine,caffeine and morphine,and antagonized the depressive effect of chiorpromazine and reserpine showed that it acted as a stimulant.In combination with either pentobarbital or mep- robamate,scopolamine at the same dose level,synergized with the depressive effects of these agents,the activity of mice being markedly decreased as if they had received large doses of the latter agents.These results showed that scopolamine acted also as a depressant.The results of combinations of other drugs showed that amphetamine synergized with caffeine and morphine and antagonized the effect of chlorpromazine and reserpine,exhibitied only central stimulating action.Chlorpromazine antagonized the stimulating effect of amphetamine and morphine and synergized with the depres- sive effect of pontobarbital,meprobamate,and reserpine,showing solely a central de- pression.Morphine however exhibited synergism with amphetamine on one hand and with chlorpromazine and reserpine on the other,showing also a dualistic action.