A modified HPLC technique for simultaneous measurement of 5-hydroxytryptamine and 5-hydroxyindoleacetic acid in cerebrospinal fluid, platelet and plasma

Abstract

A sensitive, reliable and simplified HPLC assay for simultaneous measurement of 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) in human cerebrospinal fluid (CSF), platelets and plasma is described. Perchloric acid is used for one step precipitation of proteins and extraction of 5-HT and 5-HIAA. Precision of the assay has been increased by calibration of the instrument using serotonin-free plasma spiked with known amount of standards and N-w-methyl-5-hydroxytryptamine as internal standard. Integration of the peaks and calculations are achieved by a preprogrammed data module using ratio method. As little as 20 pg/ml of serotonin in the deproteinated sample can be detected using this procedure. In a group of surgical patients, plasma 5-HT concentration is (Mean ± S D) 3.4 ± 2.7 ng/ml and that of platelet 748.3 ± 448.3 ng/10 9 platelets. In CSF, 5-HT is found to be 3.3 ± 3.4 ng/ml and 5-HIAA is 15.1 ± 7.3 ng/ml. A good correlation (r = 0.648, p< .0001) is observed between 5-HT and 5-HIAA in CSF.