Inhibition of PKC in basolateral amygdala and posterior parietal cortex impairs consolidation of inhibitory avoidance memory.

Hippocampal alpha- and betaI/betaII protein kinase C (PKC) are crucial for the formation of different types of memory in several species, including that for a one trial inhibitory avoidance (IA) task in rats. Many studies, however, have shown that other brain structures besides the hippocampus, notably the basolateral amygdala (BLA) and posterior parietal cortex (PC) are also necessary for memory consolidation. Here, we examine the role of alpha- and betaI/betaII PKC in the BLA and PC on the consolidation of the memory for IA in rats. The selective inhibitor of alpha- and betaI/betaII-PKC Go 6976 and the nonselective PKC inhibitor Go 7874 were administered into these structures at different times after training at concentrations known to inhibit PKC and to produce retrograde amnesia when given into the hippocampus. Go 7874 blocked consolidation of IA memory when infused into BLA immediately and 30 min or into PC 180 to 360 min posttraining. Go 6976 caused amnesia when given into the BLA also immediately or 30 min posttraining but in the PC hindered memory retention only when infused 270 and 360 min after the training session. Our data indicate that alpha- and betaI/betaII-PKC are critical for consolidation of IA memory shortly after training in BLA and that, first other isoforms and subsequently the alpha- and betaI/betaII PKC are required 3 or more hours after training in the PC. The findings on BLA are similar to those previously reported in the hippocampus, but those on PC suggest an entirely different molecular dynamics for memory formation in that area.