[The activation of the transcription factors of the CRE and AP-1 families correlates with the development of plasticity in Helix].

By means of gel retardation assay the DNA-binding activity of transcription factors of CRE and AP-1 families was determined in adult and juvenile (incapable for conditioning) Helix snails. The presence of DNA-binding factors of the CRE and AP-1 families was shown in adult snails. The active factors only of the CRE family were present in juveniles. Activity of these factors increased during incubation with serotonin (10(-4) M) and forscolin (5 x 10(-5) M). Both serotonin and forscolin modulate learning in adult snails. Absence of activity of AP-1 family transcription factors (the products of early fos and jun genes in juvenile snails belong to AP-1 family) may underlie the incapability for sensitization and avoidance conditioning in juvenile snails.