Nitroxidergic innervation of human cerebral arteries.

A dense network of nerves containing neuronal nitric oxide synthase is present in cerebral vessels from experimental animals. The nerves may regulate cerebrovascular tone, protect the brain from stroke, and contribute to cluster headaches in humans; but studies in humans have shown only modest nitroxidergic innervation of cerebral vessels. We tested the hypothesis that nerve fibers containing neuronal nitric oxide synthase richly innervate human cerebral arteries. We used immunohistochemical techniques at post mortem and found dense neuronal nitric oxide synthase nerve staining in human cerebral vessel walls consistent with participation of nitroxidergic fibers in human physiological and pathophysiological processes.