Mating increases the synthetic activity of the neurosecretory caudodorsal cells of Helisoma duryi (Mollusca: Pulmonata)

Abstract

In Helisoma duryi, virgin snails lay significantly fewer eggs than mated snails. It is generally accepted that in basommatophoran pulmonates, the neurosecretory caudodorsal cells located in the cerebral ganglia produce a hormone that regulates egg laying. The synthetic activity of the caudodorsal cells in Helisoma has been measured in vitro and in vivo using tritiated leucine. Virgin and castrated snails (reproductively inactive) showed significantly reduced levels of [3H]leucine incorporation compared with first-mated snails (24 and 48 h postmating). This increase in synthetic activity following mating was corroborated by autoradiography at the light microscope level which localized transport of caudodorsal cell neurosecretory proteins to the cerebral commissure, the neurohaemal area. Mating triggers an increase in synthetic activity of the caudodorsal cells.