The autonomic innervation of the vasa nervorum.

Using catecholamine fluorescence and histochemical cholinesterase staining combined with quantitative image analysis a direct autonomic innervation of arteries, arterioles, venules, veins and arterio-venous anastomoses within peripheral nerves was demonstrated in normal as well as in chemically sympathectomized rats. The adrenergic nerves carry varicosities and were more diffused than acetylcholinesterase-containing nerves; the arteries and the arterio -venous anastomoses were more richly innervated. The findings that acetylcholinesterase-positive nerve fibres were unalterated by chemical sympathectomy and were revealed by short incubation times are indicative of a true cholinergic, and probably parasympathetic, innervation of the vasa nervorum. The possible importance of the autonomic innervation of the vasa nervorum in the pathogenesis of some diseases of peripheral nerves is discussed.