[Character of liver mechanoreceptor spike activity after stopping blood flow through the hepatic veins]

The spontaneous activity and responses of hepatic mechanoreceptors to an increase in the portal circulation volume were examined before and after the stopping of the outflow from hepatic veins in anesthetized cats. Most of spontaneously "silent" receptors responded with high frequency impulses immediately after the clamping of the hepatic veins. In the units with a low resting activity, there took place a gradual increase in discharge frequency and its peak was seen 2--6 minutes later. In the units with high initial activity, the impulsation disappeared completely 0.5--1 min after the stopping of the outflow. The responses to an increase in the portal circulation volume during the stopping of the outflow was absent in all the units. After removal of the venous clamp the activity of these units returned to the initial level and so did the responses to an increase in the portal circulation volume. An importance of afferent signalization of hepatic mechanoreceptors is discussed for water-salt homeostasis control in pathological conditions in which the normal venous outflow is deranged.