The noradrenergic innervation of the vasa nervorum in old rats: a fluorescence histochemical study

The effect of ageing on the density and pattern of noradrenergic nerves in the perivascular nerve plexus supplying the vasa nervorum of the rat sciatic nerve was studied using combined catecholamine histofluorescence and quantitative image analysis techniques. The density of noradrenergic fibres around arteries and arterioles of the rat sciatic nerve vasa nervorum increased in the old animals. In contrast, no changes in perivascular nerve fibres supplying the veins and venules were found in the vasa nervorum of old rats. The increase in old age of noradrenergic innervation of arteries and arterioles of the vasa nervorum may be related to the pathogenesis of some peripheral nerve diseases.