Mortality after carotid body denervation in rats.
Serra, A., D. Brozoski, N. Hedin, R. Franciosi, and H. V. Forster.
Departments of 1Physiology and 2Pathology, Medical College of Wisconsin and
Zablocki VA Medical Center, Milwaukee, Wisconsin 53226«hyphen»0509
APStracts 8:0290A, 2001.
Carotid body denervation (CBD) in neonatal goats and piglets results in minimal irregular
breathing and no fatalities. Redundancy and/or plasticity of peripheral chemosensitivity
and a relatively mature ventilatory control system at birth may contribute to the paucity
of CBD effects in these species. In the present study, we tested the hypothesis that CBD
mortality would be greater in neonates of a less mature species such as the rat. We found
that the mortality in rats denervated at 2-3 and 7-8 days of age was significantly higher (P
< 0.05) than in sham-CBD rats. In all surviving rats, pulmonary ventilation during
hypoxia was lower in CBD than in sham operated rats 2 days after denervation. In
surviving rats denervated at P7--P8, there was also reduced weight gain and pulmonary
ventilation during eupnea, including apneas up to 20 s in duration. However, the effects
of CBD were compensated within 3 wk after denervation. Local injections of NaCN
indicated that aortic chemoreceptors might have been one of the sites of recovery of
peripheral chemosensitivity. We concluded that CBD has higher mortality in newborn
rats than in other mammals, possibly because of the relative immaturity of these animals
at birth. Nonetheless, in survivors there was enough redundancy and plasticity in the
control of breathing to eventually compensate for the consequences of CBD.
Received 13 March 2001; accepted in final form 1 May 2001
APS Manuscript Number A293-1.
Article publication pending J Appl Physiol
ISSN 1080-4757 Copyright 2001 The American Physiological Society.
Published in APStracts on 18 June 2001