타액분비 및 선혈류 조절에 대한 내인성 산화질소의 역할

Role of Endogenous Nitric Oxide in the Control of Salivary Secretion and Blood Flow

The present study was designed to investigate whether endogenous niπic oxide(EDNO) is involved in submandibular vasodilation and salivation induced by parasympathetic nerve stimulation. Effects of NW-nitro-Larginine-methyl ester (L-NAME) which blocks the synthesis of EDNO from L-arginine on the submandibular vasodilation and salivation induced by chorda stimu1ation or administration of various vasodilators were examined in anesthetized cats. Effect of L-NAME on K+ efflux induced by carbachol was also examined using the excised submandibular slice in vitro. In the submandibular slices， acetylcholine(lO 5 molfL) or vasoactive intestinal polypeptide(VIP， 10 5 molfL) increased N02 contents， which was prevented by pretreatment with L-NAME. Salivary secretion in response to the chorda stimulation(3 V， 1 msec， 1O�20 Hz) was completely blocked by treatment with atropine(l mgjkg). Increased blood flow response to the low frequency(l， 2， 5 Hz) stimulation was significant1y reduced， whereas the blood flow induced by the higher frequency(lO， 20 Hz) stimu1ation was not affected. Lingual-arterial infusion of L-NAME(lOO mgjkg) significant1y diminished the vasodilatory and salivary responses to the chorda stimulation at all stimuli frequencies used. Intra-arterial infusion of L-NAME(100 mgjkg markedly diminished the asodilatory responses to acetylcholine(5 llgjkg)， VIP(5 llgjkg) or br때ykinin(5 llgjkg). In the excised submandibular lice，K+ efflux in response to carbachol(1O-5 molfL) was significant1y decrease by pretreatment with L-NAME(1O-5molfL). In the is이ated submandibular artery precontracted with phenyleplrrine(1O-5 molJL) ， the asore1axation induced by ACh(lO 7 molfL) was reversed into a contraction by methylene blue(lO 4 molfL). These resu1ts suggest that EDNO may play an important role in vasodilation and secretion of the submandibular gland.