Effects of Local Alterations of pCO 2 and pH on Cerebrovascular Resistance in Isolated Dog Heads ∗

Abstract

Summary

The local effects of graded increases and decreases of P_aCO₂ and pH on cerebral vascular resistance were determined in isolated dog heads. Two preparations were utilized: In the first series, a donor dog was included in the extracorporeal circulation to supply blood to the constant flow perfused, decapitate head; in the second series, the donor dog was replaced with an oxygenator-reservoir system. Results indicate that the direct effect of increasing paCO₂ and decreasing pH is a fall of cerebral vascular resistance and vice versa.