Résumé
By means of chromalum-hematoxylin and thiosulfate aldehydefuchsin stains the magnocellular neurosecretory neuron of the rat hypothalamus was studied. The cell body of neuron containing various amounts of secretory granules was large in size, with a variety of shapes. The axon of neuron showed an beaded appearance; only one in each neuron was very fine in diameter and left hypothalamic nuclei to form the hypothalamo-neurohypophyseal tract. The dendrite, in general, thicker than the axon, did not project outside of the nucleus. Many of the thick short dendrites did not contain secretory granules or only few secretory granules. The thick processes with more secretory granules were considered as dendritic processes. A number of axons and thick processes containing secretory granules also contacted with the endothelium of vessels and the ependyma of the third ventricle. In addition, a group of magnocellular secretory neurons were found in the sub-choroid plexuses of the lateral ventricle.