A comparative study on neurosecretion demonstrated by the alcian blue-alcian yellow technique in three terrestrial pulmonates (Stylommatophora)

Neurosecretion was studied in the central ganglia of three terrestrial pulmonates (Deroceras reticulatum, Arion hortensis, and Helix aspersa) with the alcian blue-alcian yellow (AB/AY) staining method. A number of neurosecretory cell types were distinguished in all three species (D. reticulatum: 9, A. hortensis: 11, H. aspersa: 13) With AB/AY the cells stain different shades of green and yellow. The histochemical differences reflect ultrastructural differences: the cell types contain elementary granules of different size and appearance. Some cell types form distinct groups of up to 50 cells, while others occur in smaller groups or as single cells. Neurosecretory axons could only be traced in a few cases to the probable neurohaemal areas. Based on the following criteria: (1) staining properties of cells (2) size of cells, (3) position of cells in the ganglia, it appears that the neurosecretory systems of the three species show great similarity, although some differences are apparent.