Aspects of the Neurophysiology of Buccinum Undatum L. (Gastropoda)

Abstract

1. Recordings have been made from various central neurones of Buccinum undatum, the common whelk, particularly in response to peripheral stimulation of the osphradium. 2. These central responses show that the osphradium is sensitive to the application of a restricted range of chemical stimuli, but insensitive to mechanical stimulation with suspended particulate matter. 3. The most pronounced central activity was seen in response to the addition of a sea-water extract of Mytilus edulis. This animal is one normally preyed upon by Buccinum. The synthetic chemicals most closely mimicking this effect were glutamic and aspartic acids, which were effective at low-threshold concentrations. Other chemicals of 4-6 carbon-atom chains with terminal carboxyl groups were effective stimuli and it therefore appears that the dicarboxylic nature of the effective amino acids plays a major part in the stimulatory process. 4. Intracellular recordings indicate that the peripheral input from osphradial chemoreceptors and mantle mechanoreceptors may be either excitatory, inhibitory or without effect on central neurones.