%0 Journal Article %A Robert Ader %A Daniel W. Clink %T EFFECTS OF CHLORPROMAZINE ON THE ACQUISITION AND EXTINCTION OF AN AVOIDANCE RESPONSE IN THE RAT %D 1957 %J Journal of Pharmacology and Experimental Therapeutics %P 144-148 %V 121 %N 1 %X The present study was designed to determine the effects of chlorpromazine on the acquisition and extinction of a conditioned avoidance response. On the basis of acquisition rates, chlorpromazine and placebo groups were divided into drug and control groups for purposes of extinction. It was found that: Animals under the influence of chlorpromazine are significantly inferior to controls in acquiring the avoidance response. Increasing the dosage of chlorpromazine increases the number of trials required to attain the acquisition criterion. Without regard for the conditions under which the response was acquired, chlorpromazine (1.5 mgm./kgm.) decreases resistance to extinction. Whereas there were no differences in comparable groups under the smaller dosage, 3.0 mgm./kgm. of chlorpromazine decreases the resistance to extinction of animals having acquired the response under placebo. %U https://jpet.aspetjournals.org/content/jpet/121/1/144.full.pdf