Demonstration of 5-Hydroxytryptamine in Blood Platelets by a Formaldehyde-Induced Fluorescence Technique

Abstract

Blood smears from normal and reserpinized rabbits were dried in a desiccator and treated with gaseous formaldehyde. The normal blood smears showed an intense yellow fluorescence due to serotonin in platelets. Fluorescence was weak or absent in the smears of the reserpinized rabbits. A standard serotonin assay of the bloods confirmed a normal 5-hydroxytryptamine content in untreated rabbits while reserpinized rabbits had a low or zero 5-hydroxytryptamine level. This is a simple method for detecting the presence or absence of 5-hydroxytryptamine in the blood.