[Effects of minor tranquilizers and neuroleptics on open-field behavior in rats (author's transl)]

Abstract

Minor tranquilizers (diazepam, nitrazepam, oxazepam, bromazepam, medazepam, fludiazepam, meprobamate) at low doses increased ambulation score to 145 approximately 288% of control rats. Nitrazepam, diazepam and bromazepam which are potent, clinically prescribed minor tranquilizers increased the ambulation at lower doses than was seen with the other drugs. Fludiazepam and nitrazepam showed a maximum increase in ambulation at the same dose. Fludiazepam, nitrazepam and diazepam proved to have potent inhibitory effects on defecation. Trifluperidol, haloperidol and ID-4708 (a new butyrophenone derivative) and chlorpromazine when given at low doses reduced ambulation, while at higher doses defecation was inhibited. These four drugs reduced ambulation and elicited a recover in rates of defecation in methamphetamine treated rats. Clozapine, thioridazine and floropipamide inhibited defecation at nearly the same doses which reduced ambulation in rats not given the methamphetamine tratment. These three durugs reduced ambulation, but did not produce a recovery in the defecation rates in methamphetamine-treated rats. These results indicate that neuroleptics such as clozapine which rarely induce extrapyramidal side-effects when clinically prescribed, inhibit defecation at nearly the same doses which reduce ambulation. In methamphetamine-treated rats, haloperidol was 31 times more potent than chlorpromazine in inhibiting activity noted with ambulation. This ratio in open-field test was close to the ratio of potency of these drugs as antipsychotic clinically prescribed agents.