Morphometric electron-microscopic investigation of the neuronal processes in the neurohypophysis in water-loaded, normal and water-deprived rats.
The neuronal processes in the neurohypophysis of the rat were analyzed by electron microscopy and morphometry after the secretion of antidiuretic hormone had been fully suppressed by water load. The water was supplied through a catheter inserted in the external jugular vein for 1.5, 2.5 and 24 h, respectively. The neurohypophysis was also examined in normal rats and rats that had been water-deprived for 72 h. The rats were fixed through chronically implanted catheters, so that at the time of fixation the animal was uninfluenced by anaesthesia and surgery. Water load increased the density of the neurosecretory granules in the endings in the zone nearest the basal lamina of the pericapillary space. The interpretation of this is that water load fills up the readily releasable pool of the neurosecretory granules. Water-deprival increased the density of dispersed microvesicles in the endings, especially in the zone near the basal lamina, and it is suggested that the dispersed microvesicles are involved in membrane recapture.
D000704:Analysis of Variance; D000818:Animals; D003594:Cytoplasmic Granules / Q000648:ultrastructure*; D008297:Male; D008854:Microscopy, Electron; D009474:Neurons / Q000648:ultrastructure*; D009490:Neurosecretory Systems / Q000648:ultrastructure*; D010904:Pituitary Gland, Posterior / Q000294:innervation* / Q000648:ultrastructure; D051381:Rats; D012044:Regression Analysis; D014868:Water Deprivation