Serotonin-Synonyms 5-Hydroxytryptamine; 5-HT; Enteramine; Thrombocytin; Thrombotonin

A. Serotonin

Synonyms 5-Hydroxytryptamine; 5-HT; Enteramine; Thrombocytin; Thrombotonin;

Biological Sources The root bark of Gossypium hirsutum L. (Malvaceae) (American Unplanted

Cotton) contains serotonin.

Chemical Structure

3-(2-Aminoethyl)-1H-indol-5-ol; (C₁₀H₁₂N₂O).

Identification Tests

1. Serotonin Hydrochloride (C₁₀H₁₂N₂O.HCl) It is obtained as hygroscopic crystals, sensitive to light having mp 167-168°C. It is water soluble and the aqueous solutions are found to be stable at pH 2-6.4.

2. Serotonin complex with Creatinine Sulphate Monohydrate (C₁₄H₂₁ N₅O₆S.H₂O)

(Antemovis) It is obtained as plates which decomposes at 215°C. Its uvmax (water at pH 3.5): is 275 nm (ε 15,000). It has two dissociation constants pK₁' = 4.9 and pK₂' = 9.8. The pH of a 0.01 molar aqueous solution is 3.6. It is found to be soluble in glacial acetic acid; very sparingly soluble in methanol and ethanol (95%); and insoluble in absolute ethanol, acetone, pyridine, ethyl acetate, chloroform, benzene and ether.

Uses

1. It is a potent vasoconstrictor.

2. It is also a neurotransmitter in the CNS and is important in sleep-walking-cycles.