Can hepatic coma be caused by a reduction of brain noradrenaline or dopamine?

Abstract

Intraventricular infusions of octopamine which raised brain octopamine concentrations more than 20,000-fold resulted in reductions in brain noradrenaline and dopamine by as much as 90% without affecting the alertness or activity of normal rats. As this reduction of brain catecholamines is much greater than any reported in hepatic coma, the authors do not believe that values observed in experimental hepatic failure have etiological significance for the encephalopathy that ensues.