Neurosecretion and Molting in Some Parasitic Nematodes

Abstract

The adult female of Ascaris lumbricoides possesses a number of nerve cells containing material which stains with paraldehyde-fuchsin. Among others, most of the primary sensory cells in the lips are fuchsinophilic. Ascaris does not survive outside its host, so that it is impossible to ascribe a function to these cells. Phocanema decipiens possesses similar cells in the dorsal and ventral ganglia which exhibit a cycle of secretion correlated with the burst of cytological activity which accompanies the deposition of the new cuticle. Ligation experiments have demonstrated that a new cuticle can be deposited in the absence of these neurosecretory cells. Our most recent experiments suggest that the neurosecretory cells may control the release of leucine aminopeptidase in the excretory gland, a substance which is thought to be responsible for ecdysis.