PRODUCTION OF PROSTAGLANDIN-E2 AND PROSTAGLANDIN-F2ALPHA IN THE FRESH-WATER MUSSEL LIGUMIA-SUBROSTRATA - RELATION TO SODIUM-TRANSPORT

  • 1 January 1983
    • journal article
    • research article
    • Vol. 226  (2) , 455-461
Abstract
Phamacological experiments indicate that prostaglandins (PG) have a role in the control of Na regulation in freshwater mussels and the mechanism may be linked to cAMP and serotonin. Radioimmunoassay was used to investigate the ability of freshwater mussels to synthesize PG. The levels of precursor fatty acids were determined in a gas-liquid chromatograph. Arachidonic acid (precursor to the diene PG) was the major fatty acid component of total lipids in the gill and accounted for 14% of the total. Gill homogenates synthesize PG-like material from [3H]arachidonic acid. Material corresponding to PGE2 and PGF2.alpha. were identified on thin-layer radiochromatograms. Gills (the primary site of Na transport) can evidently produce PG. The presence of PG in freshwater mussels was verified by radioimmunoassay of blood. Both PGE2 and PGF2.alpha. were identified using highly specific antisera. The concentrations of both PG was significantly reduced when the mussels were injected with inhibitors of phospholipase A2 or cyclooxygenase before sampling blood. Stimulation of Na transport by serotonin and cAMP results in a depression of blood PGE2 with no effect on circulating PGF2.alpha.. PGE2 levels are inversely correlated with net Na flux. Endogenous PGE2 evidently negatively modulated Na transport and PGE2 levels are regulated by a serotonin-cAMP mediated system.