Uptake and metabolism of noradrenaline by blood vessels of perinephritic hypertensive dogs

Abstract

Tissue noradrenaline content as well as uptake and metabolism of tritiated exogenous noradrenaline were studied comparatively, in vitro in mesenteric arteries, and in saphenous veins of normotensive and perinephritic hypertensive dogs. The influence of cocaine, iproniazid and 3'-4'-dihydroxy-2-methyl-propiophenone (U-0521) on these variables was also investigated. The concentration of (-)-7-3H-noradrenaline used was 1.08 microM. No changes were observed in noradrenaline content, uptake and metabolism in saphenous vein strips obtained from normotensive or hypertensive animals. However, in mesenteric artery strips obtained from hypertensive dogs, a marked reduction in endogenous noradrenaline content was observed as well as a reduction in noradrenaline accumulation (20 weeks after surgery). The deamination pattern was also modified in these strips: the formation of DOPEG was markedly diminished and the formation of DOMA was increased. These results agree well with the degeneration of the sympathetic innervation of the mesenteric arteries of hypertensive dogs described by Azevedo et al. (1981).