Immunohistochemical detection of the activation of CREB and c-Fos transcription factors in the nervous system of the terrestrial snail induced by pentylenetetrazole.

Phosphorylation of CREB transcription factor and expression of the immediate early gene c-fos in the brains of vertebrates play a key role in the molecular genetic mechanisms of long-term neuronal plasticity. The present study identifies the conditions for immunohistochemical detection of pCREB and c-Fos in the nervous system of the mollusk Helix lucorum (Pulmonata: Stylommatophora); activation of these transcription factors was demonstrated after administration of the convulsive agent pentylenetetrazole. Basal pCREB and c-Fos levels in the central nervous system of intact animals were low. Injection of pentylenetetrazole at a dose of 600 mg/kg evoked characteristic stereotypical motor responses, along with sharp reductions in the phosphorylation of CREB1 and expression of the immediate early gene c-fos, this also occurring in identified neurons. Double immunofluorescent labeling of pCREB and c-Fos showed that expression of c-Fos transcription factor was seen only in pCREB-immunoreactive neurons. These data provide evidence that activation of pCREB and c-Fos transcription factors can be used as molecular markers for mapping the processes of neuronal plasticity in the nervous systems of mollusks.