Effects of in-vivo administration of taurine and HEPES on the inflammatory response in rats.

The effect of in-vivo administration of N-2-hydroxyethylpiperazine-N'-2- ethane sulphonic acid (HEPES) and taurine on rat paw oedema and reactive oxidant production was examined. Carrageenan-induced paw oedema was attenuated following intraperitoneal injection of HEPES. Chemiluminescence production by isolated peripheral blood mononuclear cells (PBMC) was reduced in HEPES-treated rats. Taurine-treated rats did not exhibit attenuation of paw oedema using subcutaneous or intraperitoneal administration but intracerebroventricular administration produced a significant reduction at a dosage of 4.0 mumol. No reduction in chemiluminescence production was observed by PBMC using subcutaneous or intraperitoneal administration of taurine, but intracerebroventricular administration produced a significant reduction at a dosage of both 0.4 and 4.0 mumol. Intravenous injection of [14C]HEPES or [3H]taurine demonstrated rapid clearance with a significantly longer half-life of HEPES compared with taurine. These results support previous reports of anti-inflammatory activity of taurine when administered centrally. The lack of anti-inflammatory effect when taurine was administered subcutaneously or intraperitoneally may be a consequence of rapid distribution or clearance. The greater anti-inflammatory effects of HEPES compared with taurine may be due to its slower distribution or clearance in-vivo.