Identification of peripheral chemoreceptor stimuli

This short review considers the essential structure and stimulus-response characteristics of the carotid body chemoreceptors and attempts to relate the latter to their role in the generation of exercise hyperpnea. It shows that the arterial chemoreceptors do contribute substantially to the drive to breathe in exercising man and it suggests that this extra drive results from an increase in discharge which occurs in spite of the fact that the classical stimuli to its discharge, do not change. The possibility that in exercise the carotid body is excited by activation of its sympathetic innervation, and by raised arterial potassium, is considered. The idea that breath-by-breath oscillations of arterial blood gas tension convey accurate information about the whole body rate of carbon dioxide production is described and found wanting.