Meeting Abstract
P2.11 Tuesday, Jan. 5 Presence of Octopamine in Hemolymph and Tissues of Crassostrea viginica and its Possible Role as a Cardio-Regulatory Hormone PRYCE, K.*; SAMUEL, D.; MYRTHIL, M.; CATAPANE, E.J.; CARROLL, M.A.; Medgar Evers College, Brooklyn catapane@mec.cuny.edu
Octopamine (OA), a biogenic amine first identified in octopus, has been well studied in arthropods and a few gastropods. It is a neurotransmitter and hormone. OA has rarely been reported in bivalves and not reported in Crassostrea virginica. We used HPLC and Competitive ELISA to identify and measure OA in cerebral and visceral ganglia, gill, palps and hemolymph of C. virginica. HPLC was performed with an isocratic, ion-pairing Phenomenex Gemini 5µ C18 column with a Beckman HPLC system and Jasco FP 2020 Spectrofluorometer. A Competitive ELISA was performed using wells coated with conjugated OA (BSA-G-OA) followed by standards and samples treated with primary anti-OA antibody. After washing, a HRP-labeled secondary antibody was applied and a colormetric reaction quantified in a Molecular Devices SpectraMax M5 plate reader. HPLC showed OA present in ng amounts in gill, palps, cerebral and visceral ganglia, and hemolymph. OA levels increased after treatment with tyramine, an OA precursor. The OA peak was verified by injecting samples spiked with standard OA. ELISA confirmed the presence of OA in the samples. To determine a possible physiological role of OA in C. virginica, heart preparations were prepared in situ by removing right shells and connecting the ventricle to an isotonic transducer. Heart rate was monitored with a Narco Systems Physiograph. Basal rates averaged 5.6 beats/min. Superfusion of OA (10 μM – 1 mM) increased it in a dose dependent manner. The study identifies OA in the nervous system, innervated organs and hemolymph of C. virginica by two methods and shows a possible physiological role as a cardio-regulatory hormone. The physiological role of OA in C. virginica and other bivalves should be further explored. This work was supported by grants 2R25GM06003-05 of NIGMS, 0516041071 of NYSDOE, 0622197 of NSF and P382A080040 of USDE.
