Morphological aspects of the hypothalamic-hypophyseal system

Summary The neural connections of various parts of the neurohypophysis of mammals (cats, dogs, rats) were investigated with the aid of the Golgi method, the aldehyde fuchsin technique (in combination with perfusion of the vascular system with India ink gelatine) and electron microscopy. The abundant supply of the palisade zone of the median eminence with thin axon terminals of the tubero-infundibular system is described. The independence of these terminals from the axons of the magnocellular neurosecretory system of the hypothalamus, which terminate in the caudal parts of the neurohypophysis, is evident. The clearcut differences between morphology and localization of the terminals of the parvi- and magnocellular neurosecretory systems at various levels of the neurohypophysis are described. The morphological aspects of the release of neural mediators in regions of these terminals are discussed.