DISTRIBUTION OF MONOAMINE FLUOROPHORES IN HYPOTHALAMO-HYPOPHYSIAL SYSTEM OF CARDUELIS CHLORIS AND ANAS PLATYRHYNCHOS

Neurons and neuropile structures of the infundibular and ventromedial nuclei of the hypothalami of the greenfinch (Carduelis chloris) and the mallard (Anas platyrhynchos) displayed a green-yellow fluorescence with the method of Falck and Owman. The fluorescence of the basal layer of the infundibular nucleus in both of these species is significantly stronger than that of the middle and dorsal layers of this nucleus. Fine fluorescent granules can be observed in a subependymal zone in the median eminence of both species. The palisade layer shows only a weakly fluorescent margin; only in two of 65 greenfinches investigated was it possible to demonstrate here a stronger fluorescent band. The fluorescence was stronger in the anterior median eminence, which is aldehydefuchsin positive, than in the posterior median eminence. From the anterior part of the median eminence and from the infundibular nucleus, it was possible to trace fluorescent fibers to the lateral cell groups of the supraoptic nucleus; the origin of this tract is unknown. The nonfluorescent perikarya of the supraoptic nucleus lie in a meshwork of fluorescent fibers. The results of treatment with reserpine and microspectrographic analysis (maximum emission at 485 nm) suggest that the fluorescence of the tuberal nuclei is attributable to monoamines (dopamine and norepinephrine). A differentiation of dopamine and epinephrine in the hypothalamo-hypophysial system of Carduelis chloris and Anas platyrhynchos has thus far not been possible by fluorescence microscopy. © 1969 Springer-Verlag.