Presence of octopamine and octopamine receptors in ganglia and tissues of Crassostrea virginica

Abstract

Octopamine (OA) a biogenic amine first identified in octopus is well studied in arthropods and gastropods being a neurotransmitter and hormone. OA has rarely been reported in bivalves. Using HPLC and ELISA we showed it present in ganglia and tissues of the oyster Crassostrea virginica, the mussel Mytilus edulis, and clam Mercenaria mercenaria. We found it cardio‐excitatory in oyster and mussel, but cardio‐inhibitory in clam. We localized OA and OA receptors in tissues using immunohistofluorescence. We used pan TAAR 1E antibodies, which react to OA, beta‐phenylethylamine, p‐tyramine and tryptamine receptors, but not classical biogenic amines and histamine receptors, and visualized with FITC conjugated 2E antibodies. Tissues were fixed with paraformaldehyde, treated with 1Eand 2Eantibodies, paraffin embedded, sectioned and viewed with a fluorescence microscope. To detect OA we used anti‐OA 1E antibody (OA conjugated to KLH), and visualized with FITC conjugated 2E antibodies. Tissues were fixed with EDAC treated with 1E and 2E antibodies and paraffin embedded and sectioned or frozen, cryostat sectioned and viewed. The TAAR antibodies revealed OA receptors in cerebral and visceral ganglia, heart, gill, adductor muscle and digestive tract. OA antibodies revealed OA in cerebral and visceral ganglia, heart and blood cells in the gill blood channels. The study shows the presence of OA receptors and OA in ganglia and organs of the oyster. The distribution of the OA fluorescence as well as previous HPLC data suggests it may be a hormone in the animal as it appears to be very wide‐spread. The work was supported by 0516041171of NYSDOE and 0622197 of DUE Program of NSF.