Neurohormonal control of Na+ and Cl- metabolism in the pulmonate freshwater snail Lymnaea stagnalis.

ABSTRACT

In Lymnaea stagnalis, extirpation of the cerebral ganglia resulted in a significant decrease of the Na+ and Cl- concentrations in the haemolymph. In intact snails, injection of an extract of the cerebral ganglia stimulated the Na+ influx from the external medium in a dose-dependent way. No effect on the Cl- influx was found. Extract injections did not affect the Na+ efflux. The Na+ influx stimulating activity, in relatively high concentrations, was also present in extracts of the median lip nerve (an important neurohaemal area, originating from the cerebral ganglia). The influx-stimulating activity was heat-stable and destroyed by Pronase treatment. It is suggested that in L. stagnalis, Na+ uptake from the medium is controlled by a neurohormone produced by the cerebral ganglia.