Abstract
Studies were made on the hemodynamics in the liver of dogs during hypoxic conditions. Dogs were divided into two groups: Group A in which the periarterial nerve plexus was intact and Group B in which it was neurectomized. Dogs were anesthetized with sodium pentobarbital and given a mixture of 5% O2 and 95% N2 . Resultant changes in the blood pressure. and blood flow of the hepatic artery and portal vein were observed. (1) In the control period, the resistance in the hepatic artery and portal vein were lower in Group B than in Group A. (2) In both groups, the abdominal aortic pressure and hepatic arterial flow increased during hypoxia, but the hepatic arterial resistance did not change. (3) During hypoxia the portal venous pressure, flow and resistance did not change significantly. From the results, the change in the hepatic arterial circulation during systemic hypoxia seems to be passive, resulting mainly from change in the systemic circulation, and neurogenic control of the hepatic artery through the periarterial nerve plexus seems to be extremely slight. In the portal circulation, the influence of the increase in systemic blood pressure during hypoxia seems to be offset by increase in splanchnic vascular resistance, so that there is no apparent change in portal hemodynamics. The reason for the low portal venous resistance during the control period after section of the periarterial nerve plexus requires study.
