Benzodiazepines decrease grooming in response to novelty but not ACTH or beta-endorphin.

Excessive grooming in response to intracerebroventricular (ICV) ACTH1-24 was assayed following various doses of diazepam, chlordiazepoxide and flurazepam. Grooming scores were only affected by doses of the benzodiazepines higher than those that depressed locomotor activity. Similarly, diazepam did not affect excessive grooming induced by ICV beta-endorphin, nor did chronic chlordiazepoxide affect ACTH-induced grooming. By contrast similar doses of the benzodiazepines decreased the increased grooming score observed when mice were observed in a novel as opposed to the home cage. This result is consistent with the hypothesis that novel cage-induced grooming is caused by an increase in the ventricular content of ACTH or beta-endorphin, and that the benzodiazepines decrease or prevent this increase. It is not consistent with hypotheses of a functional antagonism between ACTH and benzodiazepines, at least insofar as the mechanisms involved in the production of grooming are concerned.