A RAPID AND SIMPLE METHOD FOR THE DETERMINATION OF PICOGRAM LEVELS OF SEROTONIN IN BRAIN TISSUE USING LIQUID CHROMATOGRAPHY WITH ELECTROCHEMICAL DETECTION

A rapid and simple technique using solvent extraction and high pressure liquid chromatography with electrochemical detection has been developed for the determination of serotonin in small brain tissue samples (1-20 mg). The method has a reasonably good specificity and a very low experimental error (less than 3%s.e ., calculated from six samples processed and analysed from the same brain homogenate). The recovery of authentic 5-HT added is 80-90%. The 5-HT levels of rat whole brain was found with the present technique to be 690 ± 17.5 ng/g and of mouse neocortex 304 ± 16 ng/g. Monoamine oxidase inhibition with pargyline (2 h) increased 5-HT levels in mouse neocortex to 194 ± 15% (N = 5) of control, while reserpine depleted 5-HT to 13 ± 4% of control. The method has a sensitivity level of about 20 pg (0.1 pmol) per brain sample.