SOLVENT EXTRACTION METHOD FOR SIMULTANEOUS DETERMINATION OF NOREPINEPHRINE, DOPAMINE, SEROTONIN, AND 5-HYDROXYINDOLEACETIC ACID IN A SINGLE MOUSE BRAIN

A method is described for simultaneously determining norepinephrine, dopamine, serotonin, and 5-hydroxyindoleacetic acid in a single small piece of brain tissue. Up to 40-60 pieces of tissue can be conveniently processed at the same time. As many as 120 pieces of brain tissue as small as the telencephalon of a single mouse can be analyzed within a normal work week for NE, DA, and 5-HT, or these three amines plus 5-HIAA can be determined in about 80 individual whole brains. Recovery of 5-HIAA was 83%, and recovery of the three amines was 72-88%. A high degree of reproducibility was obtained for all four compounds and the method could be used routinely for the quantitative determination of small differences in tissue levels. It was not necessary to deproteinize with ZnSO4, as in other procedures for 5-HIAA, or to add a reducing agent to protect the compounds during homogenization and solvent extraction. Blanks for NE and DA were somewhat lower and more stable than those obtained by most other available methods, allowing increased sensitivity in their determination. © 1969.