Etude des effets du diazépam sur le comportement explorateur du Porc

The exploratory behavior of pigs was studied in two successive daily 20-mn sessions in a two-compartment box by counting the number of crossings from one compartment to the other and observing the activity patterns. Injection of 1 mg/kg diazepam before the first session increased the number of crossings without affecting the temporal decline of activity within the session; treated pigs did not attempt to escape the experimental situation and tended to be more perseverative in their activity patterns than control pigs. Injected before the second session, diazepam did not modify the exploratory behavior. There was no evidence of a state-dissociation effect in experimental groups for which the treatment condition differed from one session to the other. These results are discussed with respect to current theories about the behavioral effects of benzodiazepines.

     

Effects comparés du muscimol et du diazépam sur les inhibitions du comportement induites chez le rat par la nouveauté, la punition et le non-renforcement

Diazepam and muscimol, a direct GABA agonist, were compared on behavioral inhibition induced in rats by (1) novelty, (2) punishment, and (3) nonreward.(1) Muscimol (0.03–0.25 mg·kg^-1 i.p. 30 min before testing, or i.v. immediately before testing) failed to enhance food intake consistently in a nonfamiliar situation and (0.125–0.5 mg · kg^-1 i.p. or i.v.) to increase the ingestion of an unknown food (chocolate); (2) muscimol (0.125–0.5 mg · kg^-1 i.p. or 0.25 i.v. 10 min before testing) was ineffective in reducing the inhibition of lever presses for food elicited by the delivery of an electric shock at every eighth press; (3) muscimol (0.125–0.5 mg · kg^-1 i.p.) failed to attenuate the inhibitory effects on responding induced by the suppression of the reinforcement during extinction.Contrastingly, diazepam (2 mg · kg^-1 i.p. 30 min before testing) was found to reduce each type of behavioral inhibition.These data lend no support to the hypotheses of GABA control of behavioral inhibition and of GABA involvement in the action of benzodiazepines on inhibition induced by novelty, punishment, or nonreward.