EFFECTS OF HEPATIC NERVE-STIMULATION ON BLOOD-GLUCOSE AND GLYCOGENOLYSIS IN RAT-LIVER - STUDIES WITH IN-VIVO MICRODIALYSIS

In vivo microdialysis was applied to investigate the effects of hepati c nerve stimulation on glycogenolysis in rat liver under anesthesia. W e analyzed the norepinephrine (NE) outflow and glucose output from the liver through the measurement of NE and glucose in the microdialysis dialyzate, as well as the plasma glucose level. Stimulation of the hep atic nerves (10 Hz, 20 V, 2 ms, 20 s every minute) increased NE outflo w and glucose output from the liver. The blood glucose level increased by 1.5-1.6 times over the basal level at the end of the 10 min interm ittent stimulation. Bilateral adrenalectomy and pancreatectomy did not abolish the glycogenolysis that was induced by the nerve stimulation. Phentolamine, an alpha-antagonist; reduced the effects of nerve stimu lation on the glucose output and the plasma glucose level. Phentolamin e caused an increase in the NE outflow, Quinacline, an inhibitor of ph ospholipase A2; inhibited the glycogenolytic nerve effects without any inhibition of the NE outflow. These data show that hepatic nerve stim ulation produces glycogenolysis via alpha-adrenergic mechanism and par tly mediated by eicosanoids, and that microdialysis is a useful and si mple method for the study of liver metabolism in physiological conditi ons.