Meeting Abstract
Octopamine (OA), a biogenic amine first identified in octopus, is well studied in arthropods and gastropods where it functions as a neurotransmitter and hormone. The presence or function of OA has rarely been reported in bivalves. Previously, using HPLC we found OA in cerebral ganglia, visceral ganglia, gill, heart, palps and hemolymph of the oyster Crassostrea virginica and using immunohistofluorescence we visualized OA in cerebral ganglia, visceral ganglia, gill and heart. Our physiological studies also found that octopamine was cardio-active when applied to C. virginica and Mytilus edulis hearts. We hypothesize that OA receptors are present in the heart of C. virginica. To test this we did Western Blot analysis using and pan TAAR (trace amine-associated receptor) primary antibodies, which are reactive with OA, beta-phenylethylamine (b-PEA), p-tyramine (p-TYR) and tryptamine receptors, but unresponsive to classical biogenic amines and histamine receptors. For Western Blot analysis, heart tissue lysate was prepared by polytron disruption in ice-cold NP-40 detergent buffer containing protease inhibitor, followed by centrifugation to obtain supernatant with solubilized membrane proteins. Up to 30 µg of solubilized protein was subjected to SDS-PAGE with 10% acrylamide gels and electroblotted onto nitrocellulose. pan TAARreceptor immunoreactivity was revealed after incubation with primary antibodies followed by incubation with HRP-conjugated secondary antibodies. The Western Blot studies showed a strong bands at 85 kD corresponding to OA receptors in heart. The present project, coupled with our immunohistofluorescence and cardio-physiology studies, confirms the presence of OA receptors and furthers the understanding of a physiological role for OA in C. virginica. This work was supported by grant 0516041071 of NYSDOE.
