Age-related changes in the noradrenergic innervation of the coronary arteries in old rats: a fluorescent histochemical study.

Age-related changes in the density of the noradrenergic perivascular plexus supplying the coronary vessels in the rat were studied using the glyoxylic acid fluorescence technique. A marked decrease in the density of the noradrenergic innervation of large, medium and small size coronary arteries was observed in 25-month-old rats. In contrast, the fluorescent nerves supplying the coronary veins were not decreased in old animals. The present data are indicative of an age-related reduction of fluorescent noradrenergic nerves in the rat coronary arteries.