Influence of maturation and ageing on the biotransformation of noradrenaline in the rat
The present investigation was undertaken to study the influence of maturation and ageing on the disposition of noradrenaline by the aorta, heart (ventricle), liver and kidney of the rat. Slices of these tissues taken from rats aged less than 18 h, 2.5–3 months or 18–24 months were incubated with 0.1 μmol.l-1 3H-amine during 30min. At the end of this period, the accumulation of the intact amine in the tissue, as well as the 3Hmetabolites formed (3,4-dihydroxyphenylethylglycol, 3,4-dihydroxymandelic acid, normetanephrine and O-methylated deaminated metabolites) were determined by scintillation counting. The results obtained show that in the rat: 1) at any age, noradrenaline is preferentially deaminated; 2) while the capacity of the sympathetic nerve terminals in accumulating noradrenaline is rather well developed at birth, the metabolic system for its degradation is still immature; 3) aldehyde dehydrogenase activity or that of its co-factor (or both) of the heart is apparently missing at birth; 4) removal of noradrenaline by the liver and the kidney did not change with ageing, while that by the aorta decreased and that by the heart increased.
KeywordsNoradrenaline Content Sympathetic Nerve Terminal Total Metabolite Aldehyde Dehydrogenase Activity Extraneuronal Uptake
Unable to display preview. Download preview PDF.
- Guimarães S, Paiva MQ, Moura D, Vaz-da-Silva M (1991) Presynaptic α-autoadrenoceptors on peripheral noradrenergic neurones of newborn rabbits and dogs. In: Langer SZ, Galzin AM, Costentin J (eds) Presynaptic receptors and neuronal transporters. Pergamon Press, Oxford, pp 11–14 (Advances in the Biosciences 8)Google Scholar