Quantitative localization of biogenic amines in the spinal cord

Recently developed highly sensitive radiometric assays for biogenic amines have been combined with microdissection techniques to localize and quantify these amines in different structures, and at various levels of rabbit and rat spinal cords. Assays were performed for serotonin, norepinephrine, dopamine and epinephrine. It was generally found that the highest concentrations of those biogenic amines were found in the lateral and ventral horns, slightly lesser concentrations were found around the central canal, and still lower concentrations were found in the dorsal horns. Relatively low amine concentrations were found in the white matter. These biochemical measurements correlate well with localizations indicated by histofluorescence methods but provide precise quantification. Comparisons with previously available, less sensitive biochemical measurements are discussed.