This volume comprises the edited proceedings of the International Taurine Sympo sium held in Osaka, Japan, in June 1995, as a Satellite Symposium of the 15th Biennial of the International Society for Neurochemistry. This Taurine Symposium was the Meeting latest in a series held since 1975 at approximately two-year intervals by an informal group of international researchers. It attracted contributions from 20 countries, ranging from Armenia via Finland and Spain to the United States. Some 121 participants attended. The Symposium was organized and chaired by Junichi Azuma, University of Osaka. Other members of the Organizing Committee in Japan consisted of Kinya Kuriyama and Masao Nakagawa, both from the Kyoto Prefectural University of Medicine, and Akemichi Baba, from Osaka University. The Committee had to contend with the disaster of the Kobe earthquake, which struck on January 21. The epicenter was only around 25 miles from the meeting site, and the quake demolished the home of one Committee member. Despite this unnaturally natural handicap, the participants experienced a superbly organized meeting, one which more than maintained the high social and scientific standards established for this series. In his Welcome Message, Dr. Azuma listed a threefold objective for the Symposium: To provide a forum for the interdisciplinary exchange of information on taurine; to give an opportunity for renewing old friendships and making new friends; and to promote coopera tion among participants from around the world."

I was pleased and at the same time filled with some misgivings when Professors Alberto Giotti end Ryan Huxtable asked me to introduce this book. The book is the outcome of the Symposium held in Firenze-San Miniato (PI), October 6-9, 1986. The symposium was entitled "Sulfur Amino Acids, Peptides and Related Compounds" and was the 7th international symposium on taurine ssnd assooiated substances. It is always difficult to introduce, with the right brevity end emphasis, a topic which has been studied in depth by numerous experte. Nevertheless, I shall do my best to give a historical perspeotive of the subjects of the meeting which I consider to be very important for the frontiers of researoh on taurine. ~he following topios have also beoome coherent areas of study during the development of researoh on taurine: metabolism, nutrition, neurochemistry, cardiovasoular regulation. Although taurine was isolated in 1821 by ~iedman and Gmel1n, its only biochemioal role known at the time was the synthesis of bile saIte in mammalian tissue. There has been an inoreasing interest in the biologioal action of taurine from metabolio aspects to other biologioal aspects (nutrition, development, eto.). In 1975 it was first demonstrated that taurine deprivation produoed retinal degeneration in cats; more reoent studies showed that a taurine-free diet or the administration of taurine transport inhibitors caused retinal degeneration in other mammlas. More reoent studies have pointed out the role of taurine in development, and the first part of this book is dedicated to these topios.

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 0.3-3M. 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 .

There can be few elements with a biochemistry as coherent as that of sulfur. This important element is crucial to myriad aspects of metabo lism, catalysis, and structure. The plurality of functions in which sulfur is involved derives squarely from the numerous oxidation states in which it may exist, some having great stability, some being capable of ready redox interconversions, and yet others having great instability. As a result, the flux of sulfur from the geosphere through the various kingdoms of life leaves few biochemical processes unaffected. Although there are large gaps in the fabric of our basic knowledge of sulfur biochemistry, it is sufficiently framed to allow a unified and organized story, a story which many of the best-known names in bio chemistry have helped to write. It has been both a task and a privilege to try and summarize this story, one that is enormous, complex, fast moving, still developing and, above all, exciting. I suppose that no mo nographer of such a vast subject could be satisfied with his efforts. It is unfortunately probable that in attempting this task I have made as many errors as a Stilton cheese has blue streaks, and as many omissions as a Swiss cheese has holes. Perfection is not to be achieved in a monograph. Inasmuch as I have succeeded, the credit belongs to those whose efforts gave us the knowledge we have. Where I have failed, the fault is only mine."

This volume is the selected, edited proceedings of the International Taurine Sympo- th sium held in Tucson, Arizona, in July 1997. The meeting was a satellite symposium ofthe 16 Biennial Meeting of the International Society for Neurochemistry, which was held in Boston immediately following the Tucson meeting. In view of the desert location of Tucson, the meeting was advertised tongue-in-cheek as being the hottest scientific meeting ever. As the weather lived up to its billing, the Symposium may well have earned the title. The meeting was held in an atmospheric cluster of adobe buildings, old by the stan- dards of the American southwest, at the Westward Look Resort in the Sonoran Desert foot- hills of Tucson, which is overlooked by the 9000' high Santa Catalina mountains. As is the norm for taurine symposia, participants formed a multinational group, with representatives from China, Korea, Japan, United States, Mexico, Venezuela, Ireland, England, Spain, Italy, Finland, France, Denmark, Germany, Norway and Armenia. The meeting was organized around plenary lectures by Russell Chesney (University of Tennessee: Taurine and infant nutrition), Herminia Pasantes-Morales (National Autono- mous University of Mexico: Taurine: An osmolyte in mammalian tissues) and Kinya Kuri- yama (Kyoto Prefectural University of Medicine: Interrelationship between taurine and GABA).

Taurine, or 2-aminoethane sulfonic acid, has long been known to be the major organic product formed from the breakdown of the sulfur-containing amino acids, methionine and cysteine. It is excreted as such in the urine or as bile acid conjugates in the bile. Research over the last 25 years, however, has uncovered an amazing variety of phenomena involving taurine. Despite the fact that the mechanism of action of taurine in some of these phenomena remains to be elucidated, it is clear that taurine is of far more physiological relevance than being the mere metabolic debris of sulfur amino acid catabolism. It also has numerous pharmacological actions that are beginning to be developed, as exemplified by some of the studies reported in this volume. This volume reports the proceedings of the latest of a series of international symposia, continuing on from the initial meeting held in Tucson, Arizona, in 1975. The latest symposium was the first to be held in Germany, in Cologne from August 29 through September 1, 1993. It continued the multidisciplinary approach that has been the norm for taurine symposia. We hope the publication of the proceedings will stimulate further investigations on this simple but fascinating compound.

There can be few elements with a biochemistry as coherent as that of sulfur. This important element is crucial to myriad aspects of metabo lism, catalysis, and structure. The plurality of functions in which sulfur is involved derives squarely from the numerous oxidation states in which it may exist, some having great stability, some being capable of ready redox interconversions, and yet others having great instability. As a result, the flux of sulfur from the geosphere through the various kingdoms of life leaves few biochemical processes unaffected. Although there are large gaps in the fabric of our basic knowledge of sulfur biochemistry, it is sufficiently framed to allow a unified and organized story, a story which many of the best-known names in bio chemistry have helped to write. It has been both a task and a privilege to try and summarize this story, one that is enormous, complex, fast moving, still developing and, above all, exciting. I suppose that no mo nographer of such a vast subject could be satisfied with his efforts. It is unfortunately probable that in attempting this task I have made as many errors as a Stilton cheese has blue streaks, and as many omissions as a Swiss cheese has holes. Perfection is not to be achieved in a monograph. Inasmuch as I have succeeded, the credit belongs to those whose efforts gave us the knowledge we have. Where I have failed, the fault is only mine."

This volume is the selected, edited proceedings of the International Taurine Sympo- th sium held in Tucson, Arizona, in July 1997. The meeting was a satellite symposium ofthe 16 Biennial Meeting of the International Society for Neurochemistry, which was held in Boston immediately following the Tucson meeting. In view of the desert location of Tucson, the meeting was advertised tongue-in-cheek as being the hottest scientific meeting ever. As the weather lived up to its billing, the Symposium may well have earned the title. The meeting was held in an atmospheric cluster of adobe buildings, old by the stan- dards of the American southwest, at the Westward Look Resort in the Sonoran Desert foot- hills of Tucson, which is overlooked by the 9000' high Santa Catalina mountains. As is the norm for taurine symposia, participants formed a multinational group, with representatives from China, Korea, Japan, United States, Mexico, Venezuela, Ireland, England, Spain, Italy, Finland, France, Denmark, Germany, Norway and Armenia. The meeting was organized around plenary lectures by Russell Chesney (University of Tennessee: Taurine and infant nutrition), Herminia Pasantes-Morales (National Autono- mous University of Mexico: Taurine: An osmolyte in mammalian tissues) and Kinya Kuri- yama (Kyoto Prefectural University of Medicine: Interrelationship between taurine and GABA).

Taurine, or 2-aminoethane sulfonic acid, has long been known to be the major organic product formed from the breakdown of the sulfur-containing amino acids, methionine and cysteine. It is excreted as such in the urine or as bile acid conjugates in the bile. Research over the last 25 years, however, has uncovered an amazing variety of phenomena involving taurine. Despite the fact that the mechanism of action of taurine in some of these phenomena remains to be elucidated, it is clear that taurine is of far more physiological relevance than being the mere metabolic debris of sulfur amino acid catabolism. It also has numerous pharmacological actions that are beginning to be developed, as exemplified by some of the studies reported in this volume. This volume reports the proceedings of the latest of a series of international symposia, continuing on from the initial meeting held in Tucson, Arizona, in 1975. The latest symposium was the first to be held in Germany, in Cologne from August 29 through September 1, 1993. It continued the multidisciplinary approach that has been the norm for taurine symposia. We hope the publication of the proceedings will stimulate further investigations on this simple but fascinating compound.

I was pleased and at the same time filled with some misgivings when Professors Alberto Giotti end Ryan Huxtable asked me to introduce this book. The book is the outcome of the Symposium held in Firenze-San Miniato (PI), October 6-9, 1986. The symposium was entitled "Sulfur Amino Acids, Peptides and Related Compounds" and was the 7th international symposium on taurine ssnd assooiated substances. It is always difficult to introduce, with the right brevity end emphasis, a topic which has been studied in depth by numerous experte. Nevertheless, I shall do my best to give a historical perspeotive of the subjects of the meeting which I consider to be very important for the frontiers of researoh on taurine. ~he following topios have also beoome coherent areas of study during the development of researoh on taurine: metabolism, nutrition, neurochemistry, cardiovasoular regulation. Although taurine was isolated in 1821 by ~iedman and Gmel1n, its only biochemioal role known at the time was the synthesis of bile saIte in mammalian tissue. There has been an inoreasing interest in the biologioal action of taurine from metabolio aspects to other biologioal aspects (nutrition, development, eto.). In 1975 it was first demonstrated that taurine deprivation produoed retinal degeneration in cats; more reoent studies showed that a taurine-free diet or the administration of taurine transport inhibitors caused retinal degeneration in other mammlas. More reoent studies have pointed out the role of taurine in development, and the first part of this book is dedicated to these topios.

This volume comprises the edited proceedings of the International Taurine Sympo sium held in Osaka, Japan, in June 1995, as a Satellite Symposium of the 15th Biennial of the International Society for Neurochemistry. This Taurine Symposium was the Meeting latest in a series held since 1975 at approximately two-year intervals by an informal group of international researchers. It attracted contributions from 20 countries, ranging from Armenia via Finland and Spain to the United States. Some 121 participants attended. The Symposium was organized and chaired by Junichi Azuma, University of Osaka. Other members of the Organizing Committee in Japan consisted of Kinya Kuriyama and Masao Nakagawa, both from the Kyoto Prefectural University of Medicine, and Akemichi Baba, from Osaka University. The Committee had to contend with the disaster of the Kobe earthquake, which struck on January 21. The epicenter was only around 25 miles from the meeting site, and the quake demolished the home of one Committee member. Despite this unnaturally natural handicap, the participants experienced a superbly organized meeting, one which more than maintained the high social and scientific standards established for this series. In his Welcome Message, Dr. Azuma listed a threefold objective for the Symposium: To provide a forum for the interdisciplinary exchange of information on taurine; to give an opportunity for renewing old friendships and making new friends; and to promote coopera tion among participants from around the world."

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 0.3-3M. 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 .

There is increasing recognition of the biological importance of taurine. Disturbances in taurine metabolism are seen in dysfunction- al states as diverse as epilepsy, cardiomyopathy, Friedreich's ataxia and congestive heart failure, which combined with the antiepi1eptic and cardiotonic actions of taurine underscore the emerging clinical importance of this fascinating substance. This is the third book to appear on taurine since 1976. The last book (Taurine and Neuro1oeica1 Disorders, Raven Press, 1978) emphasized the involvement of taurine in central nervous system phenomena. These actions are further explored in this volume. In addition, nutritional aspects of taurine, particularly as these re- late to development, have been increasingly recognized to be im- portant parts of the taurine story. The marked emphasis placed on nutrition by a number of contributors to this volume is recognition of the meteoritic growth of this area. Are the multitudinous actions of taurine differential expres- sions of a universal mechanism? There is surprising unity of opinion expressed by the scientists contributing to this volume, despite their differences in viewpoint and background, as the reader, tanta- lized we hope by this remark, will discover.