Conditioned defensive reflex in the edible snail (molecular-genetic aspects).

The expression of the early genes c-fos and c-jun were studied by blot hybridization in the central nervous system of the edible snail at the consolidation stage of a conditioned defensive reflex, with the aim of investigating genomic activity in neurons during learning. The c-fos gene was shown to be present in the Helix central nervous system, and its expression was shown to increase significantly during learning. Superinduction of the c-fos gene was observed in the presence of cycloheximide, a protein synthesis inhibitor. Corasol also induced this gene. Thus, induction of the c-fos gene in Helix can be induced by agents which induce it in higher vertebrates. This suggests that expression of the c-fos gene in Helix and in higher vertebrates is regulated by closely related mechanisms. Expression of the c-jun gene was insignificant, and definitive conclusions with regard to the role of this gene in learning cannot be drawn.