[en] A fluorometric assay measuring brain tissue concentrations of norepinephrine, dopamine, and serotonin has been validated for Japanese quail. Accuracy, precision, specificity, and parallelism were determined. The sensitivity of the assays was 6 ng/tube, which allowed individual assay of 1 to 2 mg hypothalamic tissue. In Experiment 1, relatively large areas of brain from adult, reproductively active males and females were found to differ significantly in norepinephrine content in optic lobes and for dopamine in right telencephalon. A microdissection technique was used in Experiment 2 to sample small portions of hypothalamic tissue. Sex differences were observed for norepinephrine in the sections containing the lobus paraolfactorius and the preoptic, anterior, and medial hypothalamus. Differences in monoamine content were most apparent when smaller areas dissected by microdissection were analyzed. These results give evidence for sex differences in the monoamine content in specific areas of the brain.
