RT Journal A1 Bean WB T1 5-hydroxytryptamine. JF A.M.A. Archives of Internal Medicine JO A.M.A. Archives of Internal Medicine YR 1959 FD July 1 VO 104 IS 1 SP 168 OP 168 DO 10.1001/archinte.1959.00270070170026 UL http://dx.doi.org/10.1001/archinte.1959.00270070170026 AB In the ten years since sertonin, or 5-hydroxytryptamine, came out of its obscurity as a mysterious pharmacological force it has had much attention in clinical medicine and in pharmacology. All manner of studies have been done. Yet the surprising point, so excellently illustrated in this report of a symposium held in London, in April, 1957, is that not only its actions but its modes of action are still in dispute. Where it is manufactured, how it is transported, what lets it into cells, lets it out or keeps it in, and many other problems are as mysterious now as they were when serotonin first was discovered. Some of the many paradoxical effects of serotonin are clearly discussed and outlined in the individual essays of this symposium. A considerable distance separates what can be learned in an experimental laboratory and the clinical problems we encounter in sick patients. Monoamine oxidase, coagulation,