Effects of Psychotropic Agents on Motor Activity in Mice

향정신성약물이 마우스 자발운동에 미치는 영향

An animal which is placed in a new environment displays a complex behavioral pattern consisting of locomotion, grooming and rearing. This behavioral pattern is influenced by endogenous and exogenous stimuli, such as hormonal secretion, level of neurohumoral transmitters, drugs and light. It is widely known that the most tranquilizers depressed spontaneous motor activity although their mechanisms of action were different, while antidepressants stimulated except imipramine which showed various action. Until the present time, the hole-board apparatus, which gives rather subjective data, has been used extensively to study the effects of drugs on general activity and exploratory behavior in mice. Recently a new apparatus for mobility measurements, called a 'Selective Activity Meter' has been introduced. This instrument supposedly produces more objective data on activity and behavior. The purpose of the present experiment was to study the influence of psychotropics on motor activity using the Selective Activity Meter. In the experiment, various psychotropic agents such as major tranquilizers(chlorpromazine, haloperidol); minor tranquilizers(meprobamate, diazepam); and antidepressants(amphetamine, imipramine) were used. In each experiment, the drug was administered to five mice and their activity was recorded. Each experiment was run five or more times and the results are based on the mean of each trial. The results are summarized as follows: 1. The group of mice treated with chlorpromazine showed markedly inhibited motor activity in comparison with controls and the inhibitory action of chlorpromazine was shown to be more intense than any of the other drugs used in the test. Haloperidol administration yielded similar results until 60 minutes, but mice showed less inhibition of motor activity than with chlorpromazine after 90 minutes. 2. In the group treated with diazepam, there was strong inhibition of motor activity until 30 minutes, but after 60 minutes the mice showed less inhibition than with chlorpromazine. In the meprobamate group, motor activity was inhibited in a manner similar to that of other tranquilizers, but the inhibition was less than that of diazepam. 3. In the group treated with imipramine, the inhibition developed gradually after ten minutes. 4. The effects of amphetamine did not appear until 30 minutes after administration, but then there was a significant increase in the motor activity.