Taurine lowers blood pressure in the spontaneously hypertensive rat by a catecholamine independent mechanism.

Taurine, a sulfur aminoacid, has been studied for a role in blood pressure regulation since it functions as a generalized inhibitory neurotransmitter and is found in high concentrations in the myocardium. We reinvestigated the magnitude of the hypotensive effect of chronic taurine administration to the spontaneously hypertensive rat (SHR) and the role of catecholamines in such an action. The SHR received either a 1% taurine solution or tap water to drink for 16 weeks. Taurine treatment caused a significant persistent reduction in blood pressure by 4 weeks that was maximal at 16 weeks (146 +/- 6 [exp.] v 182 +/- 5 [control] mm Hg, P less than .01). While this taurine-induced decline in blood pressure in the SHR was not accompanied by alterations in plasma epinephrine levels, there was a steady 235% increment in the norepinephrine concentration from 231 +/- 31 pg/mL initially to 542 +/- 126 pg/mL at completion of the study, P less than .02. The reduction in blood pressure was associated with decreased proteinuria in the taurine-treated SHR (9.6 +/- 4 [exp.] v 21.5 +/- 7 [control] mg/24 h, P less than .02) and less cardiac and renal hypertrophy. We conclude that taurine administration results in a 20 to 25% reduction in blood pressure in the SHR. The mechanism of this hypotensive action requires further study but is independent of changes in plasma catecholamine levels. The vasodepressor effect of taurine leads to less hypertensive injury to the kidney and heart in the SHR.