The role of the carotid body in mediating the cerebrovaseular response to altered arterial carbon dioxide tension

The role of the carotid bifurcation chemoreceptors in mediating the cerebrovascular response to altered arterial P_CO2 has been suggested to be large. In the present study the cerebrovascular response to raised P_CO2 was measured in a group of baboons before and after bilateral inactivatien of the carotid bodies. The results suggest that these chemoreceptors do play a part in the cerebral vasodilator response to raised P_CO2. The role of the carotid body, however, appears to be relatively minor as it only accounted for ± 40% of the total response and became significant only at arterial P_CO2 levels of more than 50 mm Hg. It is postulated that the peripheral chemoreceptors in the carotid bifurcation mediate part of the cerebrovaseular response to altered Pa_CO2 but that the role is quantitatively small.