Cholinergic Mechanism in the Cerebrovascular Action of Carbon Dioxide

Abstract

The effect of an increase in Pa CO CO2 on cortical blood flow was tested in control animals and after atropine or eserine administration. Blood flow was measured at the tip of implanted platinum electrodes by means of the hydrogen clearance method. The results showed that, although atropine did not impede the appearance of autoregulation, it completely blocked the increase in cortical blood flow associated to a step increase in Pa CO CO2 . The effect of CO 2 on cortical blood flow was significantly greater under eserine than in untreated controls.