Carotid body O2 chemoreception: respiratory and nonrespiratory aspects.

The respiratory and nonrespiratory hypotheses of O2 chemoreception in arterial chemoreceptors have been compared to provide a perspective that both mechanisms can potentially coexist. The nonrespiratory membrane mechanism operates at a relatively higher level of PO2 and that respiratory metabolic mechanisms at a lower level. The two mechanisms may overlap in the intermediate range of PO2.