Crystalline Serotonin

Abstract

A crystalline substance was isolated from beef serum which was responsible for the vasoconstrictor activity of the serum. It was named serotonin. It is believed to be a sulfate salt which may also contain organic S. A single analysis gave the following results C, 41.4; H, 6; N, 17. The material responds positively to quantitative modifications of the Hopkins-Cole, Ehrlich, and Folin-Ciocalteu reactions. The u.-v. absorption spectrum in water at pH 5.4 has a max. at 2,750 A, Ksp (specific extinction coefficient) = 1.5 X 104; a shoulder with a point of inflection at 2,930 A, Ksd = 1.2 x104 and a min. at 2,560 A. Ksp = 1.0 X 104. Injected intraven. into dogs or cats anesthetized with pentobarbital, it produced a rise in arterial pressure which was augmented in a sympathectom-ized animal. An isolated rabbit''s ileum was contracted by injection of serotonin into the surrounding Tyrode bath,.