An improved and simplified method for the fluorometric determination of brain serotonin

Abstract

An improved method for the extraction and fluorometric determination of brain serotonin is described. By extensive modification of the Bogdanski et al. extraction procedure (1) the background fluorescence was greatly reduced, considerably less time was required for serotonin determination, and the need for an internal standard was eliminated. Serotonin fluorescence was determined on solutions of serotonin in 3 N HCl at 540 mμ. A single polarizer in the fluorescent beam removed the secondorder scatter which distorts the fluorescent spectrum of serotonin at low concentrations and permitted the use of the maximum intensity of the exciting light source. This procedure was 6 to 7 times more sensitive than the Bogdanski method and as little as 10 ng/ml of serotonin (standard solution) was detected. Determination of the concentration of serotonin in whole brain, recovery of exogenous serotonin from brain homogenates and recovery from subcellular components demonstrate the reliability of this method. © 1967.