Morphological studies on the paraneuron in spontaneously hypertensive rats.

Some of the paraneuronic cells in SHR in the prehypertensive stage were studied and compared to cells of the control. In the adrenal medulla, the area of the norepinephrine storing cell islets of SHR was about twice the size. The number of both the norepinephrine storing granules and vesicles in the cytoplasm was increased. In the anterior pituitary, percentage of the ACTH producing cell of SHR was increased. In the enterochromaffin cell, the average number of argyrophilic cells through the gut was larger in SHR. In the mast cells, an increased number of intrathyroidal mast cells was observed. These paraneuronic cells in SHR were considered to be hyperplastic and/or overactive from early stage after birth.