Carotid body oxygen sensing.
نویسندگان
چکیده
The carotid body (CB) is a neural crest-derived organ whose major function is to sense changes in arterial oxygen tension to elicit hyperventilation in hypoxia. The CB is composed of clusters of neuron-like glomus, or type-I, cells enveloped by glia-like sustentacular, or type-II, cells. Responsiveness of CB to acute hypoxia relies on the inhibition of O(2)-sensitive K(+) channels in glomus cells, which leads to cell depolarisation, Ca(2+) entry and release of transmitters that activate afferent nerve fibres. Although this model of O(2) sensing is generally accepted, the molecular mechanisms underlying K(+) channel modulation by O(2) tension are unknown. Among the putative hypoxia-sensing mechanisms there are: the production of oxygen radicals, either in mitochondria or reduced nicotinamide adenine dinucleotide phosphate oxidases; metabolic mitochondrial inhibition and decrease of intracellular ATP; disruption of the prolylhydroxylase/hypoxia inducible factor pathway; or decrease of carbon monoxide production by haemoxygenase-2. In chronic hypoxia, the CB grows with increasing glomus cell number. The current authors have identified, in the CB, neural stem cells, which can differentiate into glomus cells. Cell fate experiments suggest that the CB progenitors are the glia-like sustentacular cells. The CB appears to be involved in the pathophysiology of several prevalent human diseases.
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Section of Pulmonary, Critical Care, Sleep and Allergy, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois; Institute for Personalized Respiratory Medicine, University of Illinois at Chicago, Chicago, Illinois; Department of Pharmacology, University of Illinois at Chicago, Chicago, Illinois; and Center for Cardiovascular Research, University of Illinois at Chicago, Chi...
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ورودعنوان ژورنال:
- The European respiratory journal
دوره 32 5 شماره
صفحات -
تاریخ انتشار 2008