亚硝酸异戊酯和硝酸异山梨酯对豚鼠Oddi括约肌收缩性的作用。

The action of amyl nitrite and isosorbide dinitrate on the contractility of sphincter of Oddi of guinea-pigs.

Göcer F, Yaris E, Tuncer M

Department of Pharmacology, Faculty of Medicine, Hacettepe University, Ankara, Turkey.

Gen Pharmacol. 1994 Sep;25(5):995-9. doi: 10.1016/0306-3623(94)90109-0.

Abstract

This study was designed to investigate whether relaxation of isolated guinea-pig sphincter of Oddi preparation by nitrates is mediated by guanylate cyclase activation indirectly by nitric oxide (NO), as in vascular tissues. 2. Sodium nitroprusside, isosorbide dinitrate and amyl nitrite induced dose-dependent relaxations of Oddi's sphincter precontracted by potassium chloride (150 mM). Methylene blue (5 x 10(-5) M), an inhibitor of guanylate cyclase, did not significantly inhibit the relaxations caused by nitrovasodilators. 3. Unlike potassium chloride, acetylcholine (10(-7) - 10(-3) M) induced unsustained contractions which were significantly increased by methylene blue. NG-monomethyl-L-arginine (L-NMMA; 4 x 10(-4) M), an inhibitor of NO biosynthesis, also increased the contractile response to acetylcholine. 4. These results suggest that another mechanism rather than inhibition of guanylate cyclase is involved in the nitrovasodilators-induced relaxations and that acetylcholine releases a relaxing factor, possibly NO, that may modulate its own contraction in this preparation.

摘要

本研究旨在探讨硝酸盐对离体豚鼠奥迪括约肌的舒张作用是否如在血管组织中一样，是由一氧化氮（NO）间接激活鸟苷酸环化酶介导的。2. 硝普钠、硝酸异山梨酯和亚硝酸异戊酯可诱导由氯化钾（150 mM）预收缩的奥迪括约肌产生剂量依赖性舒张。鸟苷酸环化酶抑制剂亚甲蓝（5×10⁻⁵ M）并未显著抑制血管扩张剂引起的舒张。3. 与氯化钾不同，乙酰胆碱（10⁻⁷ - 10⁻³ M）诱导的非持续性收缩可被亚甲蓝显著增强。NO生物合成抑制剂N⁻甲基⁻L⁻精氨酸（L⁻NMMA；4×10⁻⁴ M）也增强了对乙酰胆碱的收缩反应。4. 这些结果表明，血管扩张剂诱导的舒张涉及的是另一种机制而非鸟苷酸环化酶的抑制，并且乙酰胆碱释放了一种舒张因子，可能是NO，在该制剂中它可能调节自身的收缩。