H. Tomimoto et al., DISTRIBUTION OF NADPH-DIAPHORASE IN THE CEREBRAL BLOOD-VESSELS OF RATS - A HISTOCHEMICAL-STUDY, Neuroscience letters, 156(1-2), 1993, pp. 105-108
NADPH-diaphorase (neuronal nitric oxide synthase) activity in the cere
bral blood vessels was investigated by light and electron microscopic
histochemistry to elucidate the sites of nitric oxide production. Netw
orks of adventitial nerves containing NADPH-diaphorase were distribute
d in all parts of the circle of Willis. However, NADPH-diaphorase acti
vity in adventitial nerves was much sparser in the region of the poste
rior cerebral artery, and absent in the pial arteries smaller than 100
mum in diameter. Endothelial cells were intensely stained in arteries
and arterioles. These results support the hypothesis that vascular to
ne is regulated by nitric oxide, which is derived from endothelial cel
ls and adventitial nerves.