AJP - Cell Physiology, Vol 261, Issue 1 C102-C105, Copyright © 1991 by American Physiological Society
Chronic cobalt causes hypertrophy of glomus cells in the rat carotid body
C. Di Giulio, P. G. Data and S. Lahiri
Department of Physiology, University of Pennsylvania School of Medicine, Philadelphia 19104-6085.
We tested the hypothesis that chronic cobalt administration would induce
carotid body cellular response along with polycythemia as found in chronic
hypoxia if common oxygen-sensitive mechanisms were involved in the two
instances. Morphometric studies were performed on carotid bodies in male
rats that were chronically treated with cobalt chloride (0.17 mumol/kg, ip,
daily for 6 wk) and in control rats that received blank saline injections.
The rats were anesthetized, blood samples were collected for hematocrit,
and the carotid bodies were surgically exposed and were perfused and
superfused with the buffered fixative (3% glutaraldehyde plus 1%
paraformaldehyde, pH 7.40, 330-340 mosM). The carotid bodies were
processed, and ultrathin sections were cut for electron microscopy and
morphometry of type I (glomus) and type II cells. Hematocrit increased from
44% in the control to 74% in the cobalt-treated rats, and the mean volume
of type I cells increased from 424 to 1,061 microns 3. Type II cells did
not show any significant change in size. The results suggest that cobalt
stimulated oxygen-sensitive mechanism in the glomus cells of the carotid
body and that the glomus cell is a site of oxygen chemosensing.
