Thromboxane plasma level in kappa-carrageenin-induced acronecrosis of the tail in rats.

The thromboxane A2 (TXA2) plasma level in kappa-carrageenin (KC)-induced acronecrosis in the rat tail has been studied. TXB2 as stable metabolite of TXA2 was determined by a radioimmunoassay (RIA). 30 min after KC i.v. injection, the increase in the plasma TXB2 level was highest in Barby:Wistar rats but not in Halle:Wistar rats. Lambda-carrageenin (LC) increased the TXB2 levels in both strains of Wistar rats, although it did not induce acronecrosis. Drugs inhibiting TXB2 formation, namely dexamethasone, acetylsalicylic acid, Hoe 944, R 68070 or chlorpromazine, had only a small effect on acronecrosis frequency. Heparin inhibited TXB2 formation and acronecrosis frequency while the serotonin antagonist cyproheptadine decreased only the acronecrosis frequency but caused no change in TXB2 plasma level. These data demonstrate that the kappa-carrageenin-induced acronecrosis is followed by an increased formation of TXA2 in rats.