Induced hypersensitivity to barbital in the female rat.

Female rats, treated with two daily anesthetic doses of barbital, exhibit 1 month later a significant increase in sleeping time over that of control animals. Hypersensitive animals, as compared to controls, show no alteration in liver weight (as percentage of body weight), but they manifest a significant shortening of time for induction of anesthesia. Induced hypersensitivity to barbiturates is apparently not the result of alterations in the metabolism of these agents, but it may be related to enhanced susceptibility of the central nervous system to these drugs.