[The carotid body--mechanisms of hypoxia sensing]

The carotid body is a peripheral chemoreceptor monitoring arterial blood gas tension and pH and contributing to the regulation of breathing. The molecular mechanism of oxygen sensing is unknown. However, it is hypothesised that lowering of arterial oxygen tension detected by O2 sensitive K+ channels, evokes a selective inhibition of K+ current of glomus cells, with an increase of cellular excitability. Hydrogen peroxide production within the glomus cells may serve as a messenger which regulates potasium channels or gene expression.