Norepinephrine turnover in the heart and blood vessels of rats subjected to bilateral renal infarction.

The total norepinephrine (NE) content, the uptake of [3H]NE, the turnover rate and the synthesis rate of the neurotransmitter at the heart and blood vessels have been studied during the development of hypertension in rats subjected to bilateral renal infarction. Normal and sham-operated rats were used as controls. Fifty percent of the rats with renal infarction became hypertensive. The weight of the hearts and blood vessels of the experimental animals was significantly increased 15 days after renal infarction. Changes were greater in hypertensive animals. NE concentration in the heart was slightly decreased without achieving statistical significance, while total NE content was unchanged. In the artery wall NE concentration was significantly decreased in normotensive and hypertensive operated rats. [3H]NE uptake in the heart and blood vessels was similar in experimental and control animals. In relation to NE turnover, in both the heart and blood vessels, normal and sham-operated animals behaved as one population while normotensive and hypertensive rats behaved as another population. The rate constant of NE turnover was increased in both tissues of operated experimental animals without achieving statistical significance in the case of the heart. NE synthesis rate was unchanged in the cardiac muscle but was significantly increased in the blood vessels of operated animals. Present data indicate that results describing NE dynamics in the heart cannot be extrapolated for the blood vessels level; on the other hand changes in the neurotransmitter do not seem to be related to the development of high blood pressure after renal infarction in the rat.