FLUORESCENCE- AND ELECTRONMICROSCOPIC STUDIES ON HYPOTHALAMO-HYPOPHYSIAL SYSTEM OF PASSER DOMESTICUS

In Passer domesticus, fluorescent aminergic fibers and axon terminals and dense-core vesicles of 500 to 1000 Å diameter were found in the perikarya and the neuropile of the infundibular nucleus, in the neuropile of the supraoptic nucleus, in the rostral common neurosecretory pathway (region of the optic chiasma), in the tubero-infundibular tract, and in the reticular and palisade zones of the median eminence. 2000-2500 Å electron-dense vesicles were found in the perikarya of the supraoptic nucleus, in the proximal division of the common neurosecretory pathway and in pars nervosa of the hypophysis. After reserpine treatment, the yellow-green fluorescence as well as the dense material contained in the ∼1000 Å vesicles and partly also in the 500-800 Å vesicles disappeared. This suggested that the ∼1000 Å and the ∼500 Å dense-core vesicles in the hypothalamo-hypophysial system of Passer domesticus contain monoamines and that the infundibular nucleus is an important source of the ∼1000 Å dense-core vesicles in the palisade layer of the median eminence. © 1969 Springer-Verlag.