| Abstract: | The biogenic amines, norepinephrine and dopamine, have been localized electron microscopically in the substantia nigra, pineal body, adrenal medulla and stellate ganglion of squirrel monkeys. The method of localization has been by the use of a specific cytochemical technique, utilizing a chromium (Cr) complex with an isoquiniline derivative formed by the reaction of the unsubstituted biogenic amine with glutaraldehyde. The final reaction product, i.e., amine-glutaraldehyde-Cr, has been identified using energy dispersive X-ray analysis and the positive Cr reactive sites have been correlated with light microscopy conducted by using glyoxylic acid histofluorence. All tissues were taken from squirrel monkeys which had either been perfused with the fixative or had been perfused with an F-12 buffer prior to fixation and/or histochemical treatment. The best results were obtained from the F-12 perfusion followed by tissue being taken through the various histochemical-cytochemical procedures. The electron microscopic localization of deposits shows significantly large structures containing the Cr positive amine material. These large deposits have not heretofore been described and correlate well in size and location with what is seen with histofluorescence. This electron microscopic technique should lead to further advances in the study of biogenic amines in nervous tissue when fine structural localization, plus well preserved morphology, are essential. |
