Abstract
The permeability of the blood–brain barrier to noradrenaline was estimated in rats with bile duct ligation by intracarotid injection of [14C]-l-noradrenaline, 3H2O, and [113mIn]ethylene diamine tetraacetate (EDTA) under pentobarbitone anaesthesia. Brain uptake of [14C]noradrenaline was expressed as a percentage of that of 3H2O (brain uptake index, BUI) and corrected for the “blood background” by the 113mIn. The BUI of noradrenaline (1.20 ± 0.19) was not increased in jaundice (0.78 ± 0.18). The capacity of oxygenated homogenates of rat brain to remove noradrenaline was measured. The presence of jaundiced plasma always caused a substantial suppression of noradrenaline removal. No effect of jaundice on specific radioactive assays for catechol-O-methyl transferase (COMT) or monoamine oxidase (MAO) could be demonstrated.
