Electron Microscopic Evidence on the Significance of the Granular and Vesicular Inclusions of the Neurosecretory Nerve Endings in the Median Eminence of the Rat

Abstract

A single injection of 5 mg/kg of reserpine caused a depletion of the granules from 20% to 15% in 2 hours. The depletion affected mainly the small granules (mean 1000 A.). Twenty-four hours after the injection, the proportion of granules was only 10.5%. Large granules (mean 1330 A) had disappeared almost completely, but the number of small granules corresponded to the number In the 2-hour group. Reserpine also caused depletion of the electron dense content of individual granules and, at times, their segmentation suggesting division. A relative increase In the proportion of vesicles of larger diameter was seen.