Factors Affecting O₂ Consumption of the Cat Carotid Body

Abstract

Knowledge concerning the O₂ consumption (VO₂) of the carotid body is important in the understanding of the mechanism of discharge of the chemoreceptors. Previous studies have yielded some conflicting results. In the situ blood-perfused preparation Daly et al. (3) found an extremely high value for VO₂ of about 9 ml/100 g/min. This study is open to criticism since, in order to obtain a measurable arteriovenous (A-V)O₂ difference, blood flow was reduced to 9 µl/min. Purves (6) using more accurate techniques, was able to measure an (A-V)O₂ difference of 0.34 ml/100 ml at the normal flow rate of 41.5 µl/min yielding a VO₂ of 0.147 yl/min for the carotid body, which is not far below the value of 0.18 reported by Daly et al. (3). Purves did not give the weight of the carotid body, but assuming it was comparable to that of Daly et al. , the VO₂ would be about 7 ml/100 g/min.