Taurine Regulation of Peripheral Hemodynamics

Taurine plays an important role in the modulation of cardiovascular function by acting not only within the brain but also within peripheral tissues. We found that IV injection of taurine to male rats caused hypotension and tachycardia. A single injection of taurine significantly lowered the systolic, diastolic and mean arterial pressure blood pressure in freely moving long Evans control rats. Previousely, we found that the endothelial cells express high levels of taurine transporters and GABA_A receptors and showed that taurine activates GABA_A receptors. Thus we suggest that the functional implication of GABA_A receptors activation is the relaxation of the arterial muscularis, vasodilation and a decrease in blood pressure. Interestingly however, the effects of acute taurine injection were very different that chronic supplementation of taurine. When rats were supplemented taurine (0.05%, 4 weeks) in their drinking water, taurine has significant hypertensive properties. The increase in blood pressure was observed however only in females, males supplemented with taurine did not show an increase in systolic, diastolic or mean arterial pressure. In both genders however, taurine supplementation caused a significant tachycardia. Thus, we suggest that acute administration of taurine may be beneficial to lowering blood pressure. However, our data indicate that supplementation of taurine to females caused a significant increase in blood pressure. It remains to be seen the effect of taurine supplementation on hypertensive rats.