Alterations in hippocampal GAP-43 phosphorylation and protein level following contextual fear conditioning

C57BL/6 (B6) mice display better contextual learning than the DBA/2 (D2) mi ce. The possibility that GAP-43, is differentially affected as a function o f strain and learning was investigated in the present study. No basal diffe rence between C57BL/6J (B6) and DBA/2J (D2) mice in the amount of hippocamp al GAP-43 was observed, but naive D2 mice have slightly lower basal levels of GAP-43 phosphorylation than do B6 mice. Interestingly, alterations in hi ppocampal GAP-43 protein levels and phosphorylation state in response to tr aining for contextual learning were observed only in B6 mice. Immediate-sho cked mice, serving as nonlearning controls, showed no GAP-43 alterations, n or did D2 mice subjected to either training condition. These results sugges t that modulation of hippocampal GAP-43 may be important for contextual lea rning and that strain-specific alterations in GAP-43 may be part of a disru pted pathway in D2 mice that is essential for learning. (C) 2000 Elsevier S cience B.V. All rights reserved.