NEURAL CONTROL OF GASTROPOD BUCCAL, VISCERAL AND CARDIAC SMOOTH MUSCLE

Abstract

Publisher Summary This chapter discusses the neural control of gastropod buccal, visceral, and cardiac smooth muscle. The myogenic myocardium of gastropods may be neurally driven like buccal muscle, but it does possess an inhibitory innervation, lacking in buccal muscle. IJPs and ACh have similar hyperpolarizing effects on the AV valve of D. auricularia where IJPs can inhibit potentials even below summation frequency. Both buccal muscle and visceral muscle of gastropods appear to have a dual excitatory innervation. In the typical pattern of motility seen in the crop of A. dactylomela, large tonic contractions appear to be cholinergic, while small phasic contractions appear serotoninergic. The penis retractor muscle of H. pomatia has dual control by peripheral neurons, which elicit rhythmic activity, and by centrally controlled pathways, which elicit tonic contractions. 5HT has potentiating and destabilizing effects on both buccal muscle and cardiac muscle, which may be related to its promotion of rhythmicity in visceral muscle. A mixture of 5HT and ACh also induces rhythmicity in radular protractor of both R. thomasiana and B. canaliculatum.