Pharmacology and Neuroscience
Professor of Pharmacology
Ph.D., 1968, University of California, San Francisco
Role of Taurine in Mammalian Tissues
Taurine, 2-aminoethanesulfonic acid, is present in high concentrations in all mammalian tissues. However, the function of taurine is not known. In our laboratory we are currently investigating the effects of taurine on ATP-dependent calcium ion uptake and protein phosphorylation in the retina of the rat. While other investigators are responsible for the initial observation that taurine stimulates calcium ion uptake, we have correlated an inhibitory effect of taurine on protein phosphorylation with the stimulatory effect on calcium ion uptake. In our model, calcium ion uptake in the mitochondria is ATP-dependent. ATP also activates a kinase which phosphorylates a gate. The gate is open when phosphorylated and thus allows calcium ions to back-flow to the outside with the concentration gradient. The regulatory effect of taurine is to inhibit the kinase system thereby closing the gate and thus preventing calcium ions from leaking out of the mitochondria. The net effect is that the calcium ion concentration is the presence of taurine is increased in the mitochondria.
Our other interests involve the effects of taurine in the cardiovascular system, specifically cardiomyopathies due to diabetes and the treatment of hypertension with taurine.
X. Zhang, T.E. Tenner, Jr., and J.B. Lombardini. Inhibition of Rat Vascular Smooth Muscle Cell Proliferation by Taurine and Taurine Analogues. Biochemical Pharmacology 57: 1331-1339 (1999).
J. D. Militante and J.B. Lombardini. Taurine Uptake Activity in the Rat Retina: Protein Kinase C-Independent Inhibition by Chelerythrine. Brain Research 818: 368-374 (1999).
J.D. Militante and J.B. Lombardini. The Stimulatory Effect of Taurine on Calcium Ion Uptake in Rod Outer Segments of the Rat Retina Is Independent of Taurine Uptake. Journal of Pharmacology and Experimental Therapeutics 291: 383-389 (1999).
S.W. Schaffer, J.B. Lombardini, and J. Azuma. Interaction Between the Actions of Taurine and Angiotensin II. Amino Acids 18: 305-318 (2000).
J.D. Militante and J.B. Lombardini. The Role of Taurine in the Pathogenesis of the Cardiomyopathy of Insulin-Dependent Diabetes Mellitus. Cardiovascular Research 46:393-402 (2000).
J.D. Militante and J.B. Lombardini. Stabilization of Calcium Uptake in Rat Rod Outer Segments by Taurine and ATP. Amino Acids 19: 561-570 (2000).
J.D. Militante and J. B. Lombardini. Increased Cardiac Levels of Taurine in Cardiomyopathy: The Paradoxical Benefits of Oral Taurine Treatment. Nutrition Research 21: 93-102 (2001).
J.D. Militante and J.B. Lombardini. Taurine: Evidence of Physiological Function in the Retina. Nutritional Neuroscience 5: 75-90 (2002).
J.D. Militante and J.B. Lombardini. Treatment of Hypertension with Oral Taurine: Experimental and Clinical Studies. Amino Acids 23: 381-393 (2002).
For further information contact Dr. J. Barry Lombardini