Anticonflict action of chlordiazepoxide in rats with combined lesions

Lesions of brain areas thought to promote anxiety do not diminish the anticonflict effects of benzodiazepines (BZDs). After initial training in the lick-suppression conflict test, eight rats received electrolytic lesions of the amygdala, dorsal raphe, locus coeruleus, and mammillary bodies. Ten others received sham lesions. Postoperative testing revealed a significant increase in punished licking at two stages after surgery in lesioned animals when compared with their own preoperative baseline levels and with the punished licking of control animals. Systemic administration of chlordiazepoxide (CDP, 2.5-10.0 mg/kg) resulted in a comparable dose-dependent increase in punished licking in both groups. These results suggest that the several structures lesioned need not be intact for CDP to have an antianxiety effect. It appears that sites of anxiolytic action are much more widely spread than currently believed and that other brain areas should be considered.