thromboxane-a2--carbocyclic and Hemolysis

The two thromboxane A2 mimetics, carbocyclic thromboxane A2 (CTA2) and U-46619 (9,11-methanoepoxy PGH2) at concentrations of 400 ng/ml significantly enhanced the release of hemoglobin from both feline and human erythrocyte suspensions. This effect was significantly attenuated by the thromboxane receptor antagonist BM-13,505 indicating that the membrane leakiness is in some way receptor mediated. The effects also appear to be concentration-dependent over the range of 100-400 ng/ml. The membrane labilizing effect of thromboxane analogs is not due to a non-specific eicosanoid effect since iloprost, the stable prostacyclin analog, actually stabilized erythrocyte membranes. Moreover, synthetic thromboxane A2 exerted similar effects to that of the two TxA2-mimetics. This membrane labilizing action of thromboxanes may be important in propagating the other pathophysiologic effects of thromboxane A2 in cardiovascular disease states.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Animals; Cats; Hemoglobins; Hemolysis; Humans; In Vitro Techniques; Prostaglandin Endoperoxides, Synthetic; Thromboxane A2