CHOLINERGIC AND PEPTIDERGIC REGULATION OF SIPHON MANTLE FUNCTION IN THE ZEBRA MUSSEL, DREISSENA-POLYMORPHA/

Neurotransmitter regulation of the siphon and adjacent mantle region o f bivalves has not previously been examined. In the biofouling bivalve , Dreissena polymorpha, acetylcholine and FMRFamide both elicited cont ractions of siphon/mantle preparations. Hexamethonium bromide inhibite d acetylcholine-elicited contractions but had no effect on FMRFamide-e licited contractions. FMRFamide-like immunoreactivity and chromatograp hic evidence for acetylcholine were found in central ganglia. arid the siphon/mantle region. Extracts of siphons, gonads, and gills, separat ed on Sephadex G-25, also contained macromorecules larger than acetylc holine and FMRFamide that caused siphon/mantle contraction. These resu lts demonstrate regulation of contraction by several potential neurotr ansmitter agents in a new bivalve preparation, the siphon/mantle. (C) 1997 Elsevier Science Inc.