Anxiolytic and anxiogenic drugs: Changes in behaviour and endocrine responses

In order to examine the link between changes in behaviour in animal tests of anxiety and the corticosterone stress response, this article: (1) reviews the changes in plasma corticosterone conentrations when rats are exposed to animal tests of anxiety; (2) describes the effect in animal tests of anxiety of administering CRF, ACTH and corticosterone; (3) describes the effects of the benzodiazepines and other anxiolytic drugs on plasma corticosterone concentrations of stressed and unstressed animals; (4) describes the effects on stressed and unstressed corticosterone concentrations of administering anxiogenic drugs. It is concluded that an antistress effect is not a necessary consequence of an anxiolytic drug action and that a prostress effect may not necessarily predict an anxiogenic drug action.