Morphological basis for coordination of growth and reproduction processes in the CNS of two terrestrial snails

The morphology of cells immunoreactive to an antibody against molluscan insulin-related peptide (MIP-IR) was studied in two species of terrestrial snail: Helix lucorum L. and Eobania vermiculata L. Immunocytochemical staining with this antibody to MIP revealed 100-130 cells in the postcerebrum, located in two clusters with common pathways in the dorsal body nerve and the cerebral artery nerve. About 75% of the MIP-IR cells were labeled by backfilling of the dorsal body nerve in Helix and Eobania; the corresponding figures for labeling by backfilling of the cerebral artery nerve were about 60% in Helix and 30% in Eobania. Upon intracellular staining of neurons of the dorsomedial postcerebrum, where most of the MIP-IR cells were located, it was found that they projected either in the dorsal body nerve or in the cerebral artery nerve or in both. The obtained data suggest that growth and reproduction processes (both functions were attributed to the insulin-related peptide-containing neurons) are regulated by the two, partially coinciding subsets of postcerebral MIP-IR neurons with different types of branching.