Studies on the Neurosecretory Control of Egg Laying inAplysia

Abstract

synopsis. Studies are reviewed on the electrophysiological and endocrinological features of a group of neurosecretory cells (the bag cells) in the abdominal ganglion of Aplysia. Electrophysiological studies suggest that the bag cells are involved in the regulation of a phasic behavioral function such as egg laying. Egg laying occurs approximately one hour following the injection into the hemocele of a crude extract of the bag cells or of the perfusate of an abdominal ganglion in which a pleural abdominal connective is electrically stimulated. The bag cells appear to act as a unit, releasing a measured dose of egg laying hormone when they are triggered into activity. Studies on invertebrates have been instrumental in the development of the con? cept of neurosecretion. The majority of invertebrate studies have utilized arthro? pods, in part because of their availability and hardiness to surgical manipulations. It is difficult however to obtain intracellular recordings from arthropod neurons, and consequently most research has focused on the endocrine rather than neural aspects of neurosecretory cells in invertebrates. One group of neurosecretory cells, the bag cells of the marine mollusc Aplysia, have several features that make them very well suited for interdisciplinary study. In this paper I will review the data that have been obtained from two different types of studies on the function of the bag cells. One set of studies involved intracellular recordings of the electrical activity of the