Training in the step-down inhibitory avoidance task time-dependently increases cAMP-dependent protein kinase activity in the entorhinal cortex

The cAMP/cAMP-dependent protein kinase (PKA) signaling pathway has been imp licated in synaptic plasticity changes and memory consolidation, Several co rtical structures are involved in the consolidation of memory for inhibitor y avoidance, The aim of the present work was to observe the effects of trai ning in the inhibitory avoidance task on the levels of PKA activity in the entorhinal, parietal and posterior cingulate cortex (EC, PARIET and PC), an d the medial precentral area (Fr2) of the rat, at different post-training t imes (0, 1.5, 3 and 6 h), PKA activity, assayed using [gamma-P-32]ATP and k emptide, a selective substrate, increased in the EC 3 h after training, but no changes were observed in PARIET, PC and Fr2, These results suggest that the late phase of memory consolidation of inhibitory avoidance requires a functional PKA signaling pathway in the EC in a way that a 'peak' of PKA ac tivity is observed, (C) 2001 Lippincott Williams & Wilkins.