Membrane mechanism of neuroendocrine caudo-dorsal cell inhibition by the ring neuron in the pond snail Lymnaea stagnalis

Abstract

Ovulation in the pond snail Lymnaea stagnalis is controlled by the neuroendocrine caudo-dorsal cells (CDCs) in the cerebral ganglia, which release an ovulation hormone during a period of impulse activity. Firing of the single RN in the right cerebral ganglion hyperpolarizes the CDCs. This hyperpolarization is caused by the opening of potassium channels in the axons that connect both the CDC clusters. By this action, that presumably is mediated by axonal branches of the RN in the intercerebral commissure closely associated with these CDC axons, the RN decouples both the CDC clusters. Although the RN has negative feedback on the CDC, it does not control afterdischarge characteristics. The authors suggest that the RN, next to the egg-laying behavior, is involved in another behavior, not compatible with ovulation. Male reproductive activity is presented as a possible candidate for such behavior.