Nervous Control of the Salivary Glands of the Carnivorous Mollusc Philine Aperta

Abstract

Evidence is presented to show that the electrical activity of the salivary glands of Philine aperta is controlled by two largely independent systems which elicit different responses from salivary acinar cells. The excitatory junction potentials (EJPs) recorded from salivary cells result from the activity of a pair of identified buccal ganglion neurones. Each of these salivary effector neurones innervates only the ipsilateral gland. The effector neurones are driven to fire by synaptic input which is timed to occur during the retraction phase of the feeding cycle. Gland cell excitatory post-synaptic potentials (EPSPs) and action potentials appear to be mediated by a small group of peripheral neurones located at the base of each salivary gland. These cells give rise to a tract of fibres which cross to the contralateral gland and which may be responsible for communicating EPSP/action potential activity between the glands. The possible functions of the EJP and EPSP/spiking activities are discussed.