Intracellular regulation of plasticity in Helix.

An increase of PKA activity in the cytoplasmic membrane and nuclei of the CNS conditioned snails was shown. We also found that c-fos as present in the Helix CNS, and its expression is enhanced during learning. A translocation of the PKA catalytic subunit into the nuclei and an activation of the c-fos expression might underlie the long-term plasticity in Helix.