Effects of taurine on rat aorta in vitro.

The effects of taurine on vascular tone of isolated thoracic aortic rings were investigated. We have observed that: 1) taurine is able to induce reduction of the basal contractile tone; 2) taurine exerts a relaxing action in artery segments preconstricted with high potassium medium noradrenaline; 3) the effect of taurine is either dependent on endothelium, nor mediated by adrenoceptors or muscarinic cholinoceptors; 4) in vessels with basal tone or in those preconstricted with noradrenaline, the presence of endothelium reduces the taurine-induced relaxation; 5) the actions of taurine are independent of extracellular calcium; 6) taurine increases the vasodilatation induced by a perfusion with a calcium-free medium. The physiological role of taurine in the maintenance of vascular tone in normal and pathological situations is discussed.