Effect of nitric oxide synthase inhibitor on increase in nasal mucosal blood flow induced by sensory and parasympathetic nerve stimulation in rats.
OBJECTIVE
Neural control of nasal blood flow (NBF) has not been systematically investigated. The aim of the present study was to evaluate the effect of electrical stimulation of both sensory and parasympathetic nerves innervating the nasal mucosal arteries on NBF in rats.


METHODS
In anesthetized rats, nasociliary (sensory) nerves and postganglionic (parasympathetic) nerves derived from the right sphenopalatine ganglion were electrically stimulated. We measured NBF with a laser-Doppler flowmeter.


RESULTS
The nerve stimulation increased NBF on both sides and increased the mean arterial blood pressure. The increase in NBF was larger on the ipsilateral side than on the contralateral side. Hexamethonium bromide, a ganglion blocker, abolished the stimulation-induced pressure effect and the increase in NBF on the contralateral side, but did not abolish the increase in NBF on the ipsilateral side. The remaining increase in NBF was abolished by N(G)-nitro-L-arginine, a nitric oxide synthase inhibitor. Histochemical analysis with nicotinamide adenine dinucleotide phosphate-diaphorase showed neuronal nitric oxide synthase-containing nerves that innervate nasal mucosal arteries.


CONCLUSIONS
Nitric oxide released from parasympathetic nitrergic nerves may contribute to an increase in NBF in rats. The afferent impulses induced by sensory nerve stimulation may lead to an increase in mean arterial blood pressure that is partly responsible for the increase in NBF.
Ogawa
Fumio
F
Department of Otorhinolaryngology, Shiga University of Medical Science, Shiga, Japan.
Hanamitsu
Masakazu
M
Ayajiki
Kazuhide
K
Aimi
Yoshinari
Y
Okamura
Tomio
T
Shimizu
Takeshi
T
D000818:Animals; D004558:Electric Stimulation; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005730:Ganglionic Blockers / Q000494:pharmacology*; D018738:Hexamethonium / Q000494:pharmacology*; D017078:Laser-Doppler Flowmetry; D008297:Male; D009297:Nasal Mucosa / Q000098:blood supply*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors*; D019335:Nitroarginine / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D012039:Regional Blood Flow / Q000187:drug effects
D004791:Enzyme Inhibitors; D005730:Ganglionic Blockers; D019335:Nitroarginine; D018738:Hexamethonium; D019001:Nitric Oxide Synthase