Role of carotid chemoreceptors in control of breathing at rest and in exercise: studies on human subjects with bilateral carotid body resection.

Control of ventilation at rest and in exercise was studied in subjects whose carotid bodies were bilaterally resected (BR) for the treatment of bronchial asthma some 30 years ago. Ventilatory activities of the carotid body were estimated to be responsible for about 90% and about 30% of the hypoxic and hypercapnic responses, respectively. The BR subjects still revealed a weak hypoxic chemosensitivity, called residual hypoxic response (RHR). The nature of RHR was discussed in detail. Exercise hyperpnea was found to be depressed in the BR subjects when compared with the subjects with similarly impared pulmonary function. This result appears to support the oscillation hypothesis in explaining exercise hyperpnea.