Functional evaluation of 6-hydroxydopamine-induced sympathectomy in the liver of the cat.

Intraportal injection of 6-hydroxydopamine (25 mg/kg) results in nearly complete functional sympathectomy in the cat liver 1 week after the injection. Functional sympathectomy was verified by comparing the changes in liver blood volume (measured in vivo in a plethysmograph) resulting from direct stimulation of the hepatic nerves in control and pretreated animals. Pretreatment prevented the large reductions in hepatic blood volume normally seen with nerve stimulation while the response to infused noradrenaline was not reduced. Lack of morphological changes in right atrial nerve endings and an unaltered pressor response to bilateral carotid arterial occlusion indicate that sympathectomy at sites other than the liver did not occur.