PASSIVE-AVOIDANCE LEARNING INDUCED CHANGE IN GAP43 PHOSPHORYLATION INDAY-OLD CHICKS

Day-old chicks trained on a single trial passive discriminated avoidan ce task demonstrated a significant increase in in vitro phosphorylatio n of a 50 kDa protein in P2M fractions of total forebrain. The increas e occurred 30 min posttraining, at a time when previous reports sugges t that mechanisms for triggering protein synthesis-dependent long-term memory consolidation are activated. These changes in phosphorylation rates were accompanied by a substantial enhancement of total kinase ac tivity. Immunoblotting studies with monoclonal anti-GAP43 antibody ind icate that this protein is GAP43. These results contradict previous re ports of a decrease in in vitro GAP43 phosphorylation following the sa me learning paradigm. A number of procedural differences may account f or this discrepancy. The results suggest that changes in the phosphory lation state may be associated with mechanisms triggering long-term me mory consolidation.