Rats were treated for 5 days with vehicle or chlordiazepoxide (CDP, 5, 10, or 20 mg/kg/day) and then exposed to a cloth impregnated with a neutral or cat odor. Those exposed to cat odor made significantly fewer contacts with the cloth and spent less time in contact with it and more time sheltering than those exposed to the neutral odor. CDP (5 mg/kg) significantly increased the time in contact with both odor cloths, but there were no other significant effects in the cat odor group. Rats previously exposed to cat odor showed significant anxiogenic responses in the social interaction and elevated plus-maze tests that were significantly reversed by CDP. There was no reduction in the responses to the cat odor on a second occasion as a result of the first exposure occurring after treatment with CDP (5 or 20 mg/kg). The anxiogenic effects of pentylenetetrazole (20 mg/kg) as detected in the social interaction and plus-maze tests were unaffected by prior odor experience. It is suggested that during exposure to the cat odor the responses of rats reflect avoidance components of a phobic anxiety state. Benzodiazepines are relatively ineffective against these responses in contrast to their efficacy against the generalised anxiety responses detected in the social interaction and plus-maze tests.
Animals Anxiety