Journal of Applied Physiology, Vol 67, Issue 1 484-487, Copyright © 1989 by American Physiological Society
Metabolic activation of carotid body glomus cells by hypoxia
A. Obeso, C. Gonzalez, B. Dinger and S. Fidone
Department of Physiology, University of Utah School of Medicine, Salt Lake City 84108.
The effects of low O2 on glucose consumption in the rabbit carotid body
were studied using the in vitro 2-deoxyglucose technique. Metabolically
active structures within the tissue were localized autoradiographically
after freeze-drying and vacuum fixation/embedding of selected incubated
tissue samples. In 100% O2-equilibrated media, the mean basal glucose
consumption calculated from the rate of 2-[1,2-3H]deoxy-D-glucose
phosphorylation and its specific activity in the incubation media was 61
nmol.g tissue-1.min-1 in the carotid body and 42 nmol.g tissue-1.min-1 in
parallel experiments with nodose ganglia. Low PO2 (20% O2-equilibrated
media in vitro) increased glucose consumption in the carotid body by 44%
but did not alter glucose metabolism of nodose ganglia. Autoradiographic
data showed that preneural type I parenchymal cells are the principal site
of glucose consumption in carotid chemosensory tissue. The mechanisms
responsible for the hypoxia-induced increase in glucose consumption by the
type I cells are discussed in relation to sensory transduction by the
carotid body chemoreceptors.
