Long-Term Hypoxia and Hypercapnia in the Carotid Body: A Review

Exposure to prolonged hypoxia causes a gradual increase in pulmonary ventilation above the acute hypoxic response despite a decrease in the blood gas stimulus levels resulting from hyperventilation (1). This phenomenon referred to as ventilatory acclimatization to hypoxia has been observed in all mammalian species studied to date. Evidence has accumulated indicating that the carotid body chemoreceptors are essential to the process of ventilatory acclimatization to long-term hypoxia (2–5). The importance of the carotid bodies in this physiological adaptation is stressed further by a number of morphological, biochemical, and functional alterations of the organ in response to long-term hypoxic exposure.