The expression pattern of CREB genes in the central nervous system of the pond snail Lymnaea stagnalis.

To analyze the expression pattern of genes of cAMP responsive element binding protein (CREB), we performed in situ hybridization for the whole central nervous system (CNS) of the pond snail Lymnaea stagnalis. The CREB1 (activator) and CREB2 (repressor) homologues have already been cloned in L. stagnalis, and they are referred to as LymCREB1 and LymCREB2. Using the frozen sections and the whole mount preparations of the CNS, we mapped the distribution of LymCREB1 and LymCREB2 mRNA containing neurons. The present findings showed that the LymCREB1 mRNA containing neurons are a relatively few, whereas LymCREB2 mRNA is contained ubiquitously in the whole CNS of L. stagnalis.