MODULATION OF THE ELECTRICAL-ACTIVITY OF MOTOR-NEURONS BY NEUROPEPTIDES ENCODED ON THE CDCH-GENE OF THE POND SNAIL LYMNAEA-STAGNALIS

Egg laying in the pond snail Lymnaea stagnalis is controlled by the Caudodorsal cells, located in the cerebral ganglia of the central nervous system. These neurons produce a number of different neuropeptides that are involved in the control of egg laying and egg-laying behaviour. These peptides are released from the Caudodorsal cells prior to egg laying and are thought to act as neurohormones and neurotransmitters. Injection of single peptides into animals produced specific behavioural changes. The motorneurons that are involved in the expression of some of these behaviours have been identified. Application of some of these neuropeptides to the somata of these motorneurons produced changes in the spontaneous firing patterns of these motorneurons. It is discussed how these results are interpreted in terms of the organization of the egg-laying behaviour and the timing and localization of the release of these peptides.