Propagation of Action Potentials Through Electrotonic Junctions in the Salivary Glands of the Pulmonate Mollusc, Helisoma Trivolvis

Abstract

The secretory cells of the salivary glands of the snail, Helisoma trivolvis, exhibit regenerative, overshooting action potentials whose amplitude may exceed 100 mV. The salivary glands consist of paired, tubular, epithelial structures with acinar outpocketings. The secretory cells display extensive electrical coupling which allows action potentials to propagate along the glandular epithelium. Salivary glands from nine genera of gastropod molluscs were examined. The genera comprised one opisthobranch, one prosobranch, two terrestrial pulmonate slugs, one terrestrial pulmonate snail, and four aquatic pulmonate snails. Action potentials were recorded from all of the examined glands, suggesting that the production of action potentials in salivary glands is a general phenomenon among gastropods.