Studies on the Neurosecretory Control of Egg Laying in Aplysia

Studies are reviewed on the electrophysiological and endocrinologicalfeatures of a group of neurosecretory cells (the big cells)in the abdominal ganglion of Aplysia. Electrophysiological studiessuggest that the bag cells are involved in the regulation ofa phasic behavioral function such as egg laying. Egg layingoccurs approximately one hour following the injection into thehemocele of a crude extract of the bag cells or of the perfusateof an abdominal ganglion in which a pleural abdominal connectiveis electrically stimulated. The bag cells appear to act as aunit, releasing a measured dose of egg laying hormone when theyare triggered into activity.