The Effects Of Taurine On Excitable Tissues

It has become an annual custom for the Physiological Society of Philadel phia to sponsor a spring symposium in honor of A. N. Richards (\876-1966), a research pharmacologist who developed the classical micropuncture tech nique for studying kidney function. The A. N. Richards Symposium for 1979 was held on April 23-24 in Valley Forge, Pennsylvania. The theme of this symposium was "The Actions of Taurine on Excitable Tissues." Although taurine was discovered as a constituent of bile salts in 1857 by a chemist and an anatomist (Gmelin and Tiedemann), interest today centers chiefly on the extrahepatic actions of taurine, especially in brain, heart, and other excitable tissues. Research on taurine is clearly in a period of exponential growth. We can be sure that the research reports presented and described herein as the "Proceedings of the Symposium" will provide impetus for further growth. Thus the report describing macromolecular receptors for taurine in myocardial sarcolemma may provide a model for exploring the molecular mechanisms that underlie the action(s) of taurine. Stabilization of mem branes and modulation of ion fluxes are two fundamental actions of taurine dealt with in many of these reports. It is just these actions of taurine that have been reported by several investigators as being involved in human myotonia, diabetes, and heart failure.

Mitochondria from mammalian tissues possess an elaborate system for 2+ 2+ transporting Ca across their inner membrane which consists of Ca import, 2+ via the Ca uniporter, in response to the mitochondrial membrane 2+ + potential ?? and of Ca release by an antiport system in exchange for H + 9,23 or Na (see Fig. l) . Because the uniporter is dependent upon the external 2+ 2+ 2+ 2+ Ca concentration ([Ca ]), mitochondria accumulate Ca until the [Ca ] o o 2+ decreases to the level at which the uniporter activity balances the Ca efflux. 2+ The [Ca ] at which the uniporter and efflux activities are equal is defined o the “setpoint” andcorresponds to values between 0.3-3μM. 2+ Figure 1. The Ca transport system of the inner membrane of mammalian mitochondria. U, + 2+ + + uniporter. I, Na -independent efflux mechanism or Ca /2H exchanger. D, Na -dependent 2+ + efflux mechanism or Ca /2Na exchanger. PTP, permeability transition pore. FP, 11 flavoprotein. ?? membrane potential. ? pH gradient. Adapted from .

Taurine (2-aminoethanesulfonic acid) is an enigmatic compound abounding in animal tissues. It is present at relatively high concentrations in all electrically excitable tissues such as brain, sensory organs, heart, and muscle, and in certain endocrine glands. Some of its physiological functions are already established, for example as an essential nutrient during development and as a neuromodulator or osmolyte, but the cellular mechanisms are still mostly a matter of conjecture. Moreover, there are a number of other putative functions of taurine less well known at present. Taurine 7 contains the proceedings of the 16th International Taurine Meeting. This meeting is a multidisciplinary symposium, with participants presenting different fields of biological science. This volume focuses on all aspects of taurine research from immunology and its effect on health to chemistry and biochemistry, including future clinical applications.

In 1978, we had the first research meeting of guanidine compound analysis in Okayama, Japan. The purpose of the meeting was to standardize the methods of analyzing guanidino compounds, because the analytic methods, even, for example, that of normal plasma, were quite different from laboratory to laboratory at that time. More than ten laboratories joined in this research project. Thereafter, the purpose of the annual meetings was extended to cover general biochemistry of guanidino compounds, and every meeting has served to promote our mutual growth and progress. The last meeting of the Japan Guanidino Compounds Research Association in 1982 brought together more than 80 members, and about 30 papers were presented there. This, the 6th annual meeting, brings the International Symposium on Guani dino Compounds here to Tokyo. Recently, many scientists are engaged in the research of guanidine compounds, especially in the field of clinical bio chemistry. I am sure that the observation of guanidinosuccinic acid in the urine of uremic patients by Dr. Cohen's research group in 1963 ignited the recent exploration of the role of guanidino compounds in renal diseases. The study of guanidino compounds does, however, have a long history. The first knowledge of guanidine was obtained by Strecker in 1861 (Annalen der Chemie und Pharmacie, 118, 151- 177, 1981).

The Taurine Symposium- "Taurine: Beginning the 21'' Century"- was held September 20-23, 2002, on the beautiful island of Kauai in Hawaii. The headquarters of the meeting was the Radisson Kauai Beach Resort. This international meeting was attending by approximately 80 individuals from 23 nations and 4 continents. Seventy-five papers were presented either as platform presentations or poster presentations. Taurine, first isolated from ox bile in 1827 by Tiedemann and Gmelin and named in 1838 by Demarcay, became of significant scientific interest in 1968 when the first extensive review article was published by Jacobsen and Smith. Interest in taurine grew exponentially after 1975 when the first taurine symposium was organized by Ryan Huxtable in Tucson, Arizona. Since that date, taurine symposia have been held approximately every two years held in various cities and resort areas around the world. Taurine investigators have had the privilege of attending these scientific meetings on three continents - Asia, Europe, and North America. Since the initial meeting in 1975, a central question addressed during many of the symposia has been: "What is physiological, pharmacological, nutritional, and pathological role of taurine?". Although taurine has been established as an important osmolyte, it appears to affect many other biological processes. However, the exact mechanism(s) by "which taurine acts" has not yet been definitively answered. In Kauai, the patticipants discussed many topics and asked many questions regarding the role and actions of taurine.

Proceedings of the International Taurine Symposium '97: Neurochemistry, Biochemistry, and Pharmacology held in Tucson, Arizona, July 15-19, 1997

The underlying philosophy of these two symposia on taurine remains the same as all those that have been held previously: the best way to remain current in the subject matter is to talk directly with the investigators at the forefront of the field. Thus, we brought together some 50 individuals from 11 different countries who have keen interests and active research programs in the many-faceted areas of taurine research. The meetings were held on October 8-10, 1991, in an elegant setting in a resort area at Orange Beach, Alabama, approximately 50 miles outside of Mobile on the Gulf Coast. The meetings were programmed as two separate Symposia held sequentially. The first symposia on October 8 was devoted exclusively to taurine research in the cat, primarily in the area of nutrition, and entitled "The Waltham Symposium on Taurine and Cat Nutrition". The second symposia on October 9 and 10 was open to all fields of taurine research and was entitled "International Taurine Symposium: New Dimensions on its Mechanisms of Actions". If the philosophy of these meetings was to bring both experts and novices together in a discussion and presentation of current taurine research, then the major purpose of the Proceedings is to document the current research efforts and to present an objective summary of where the taurine field stands today and where the focus will be in the future.