The attenuation of suppression of motility by triazolam in the conditioned fear stress task is exacerbated by ethanol in mice

Abstract

We investigated whether triazolam attenuated the suppression of motility in the conditioned fear stress task in mice and whether ethanol modified the effects of triazolam. When mice were placed 24 hours later (retention test) in the same environment in which they had previously been exposed to an electric foot shock (training), they exhibited a marked suppression of motility (conditioned fear stress). Triazolam (0.01–0.1 mg/Kg, S.c.), administered before training, attenuated the suppression of motility in the conditioned fear stress task in a dose-dependent manner, without affecting the sensitivity to an electric foot shock. The doses of triazolam that attenuated the suppression of motility were much lower that those of chlordiazepoxide (5–10 mg/Kg, S.c.). Neither drug, administered before the retention test, attenuated the suppression of motility in the conditioned fear stress task. These results suggest that both benzodiazepines may inhibit the process of acquisition, but not the process of recall, of memory. Ethanol (1 g/Kg, P.o.), which, by itself, did not affect either the suppression of motility or the sensitivity to an electric fool shock, exacerbated the attenuation of the suppression of motility in the conditioned fear stress task induced by both triazolam (0.01 mg/kg) and chlordiazepoxide (5 mg/kg). These results suggest that ethanol exacerbates the effects of benzodiazepines.