TYPE-II GLUCOCORTICOID RECEPTOR ANTAGONISTS IMPAIR CONTEXTUAL BUT NOTAUDITORY-CUE FEAR CONDITIONING IN JUVENILE RATS

There is evidence that glucocorticoids may play a role in learning and memory. To further explore this possibility, we examined the effect o f the Type II glucocorticoid antagonists on contextual fear conditioni ng. This conditioning task is dependent on the hippocampal formation, a brain structure known to be rich in glucocorticoid receptors. Rats s ystemically injected with a Type II antagonist either Ih prior to cond itioning (RU 38486 and RU 40555) or immediately after conditioning dis played less contextual fear conditioning than rats injected with vehic le. Although RU impaired contextual fear conditioning, it had no effec t on auditory fear conditioning. These data are consistent with other reports that contextual fear conditioning and auditory-cue fear condit ioning depend on different processes and with the hypothesis that gluc ocorticoid activity contributes to the processes involved in the conso lidation of some forms of memory. (C) 1997 Academic Press.