Distribution of catecholamines in the sea scallop, Placopecten magellanicus

Catecholamines have previously been implicated in several important physiol ogical processes in molluscs, including reproduction, respiration, and feed ing. Much of the previous research has relied upon high-performance liquid chromatography to identify and quantify the various catecholamines and phar macological experiments to investigate their actions. In the present report , we expand upon these studies by using histochemical techniques to investi gate the distribution of catecholamine-containing cells and fibres in the c entral nervous system and peripheral tissues of the sea scallop, Placopecte n magellanicus. Strong catecholaminergic staining was present in the somata and neuropil of all major central ganglia. Catecholamines were also abunda ntly stained in peripheral neurones and (or) fibres in several other tissue s, including the labial palps, lips, intestine, gill filaments, foot, mantl e, tentacles, and gonadal integument. It is concluded that catecholamines a re widespread in the tissues of the scallop and could have potential neurot ransmission roles in both the central nervous system and peripheral tissues of this species.