Suzuki H, Gao X P, Olopade C O, Jaffe H A, Pakhlevaniants S, Rubinstein I
Department of Medicine, University of Illinois at Chicago 60612-7323, USA.
J Appl Physiol (1985). 1996 Jul;81(1):225-31. doi: 10.1152/jappl.1996.81.1.225.
The purpose of this study was to determine whether an aqueous extract of smokeless tobacco (moist snuff) modulates vasomotor tone in the oral mucosa in situ and, if so, to determine the mechanisms that mediated these responses. Using intravital microscopy, we found that the extract had no significant effects on diameter of resistance (second-order) arterioles [44 +/- 5 (SD) microns] in the hamster cheek pouch. However, it significantly attenuated vasodilation elicited by two endothelium-dependent agonists, acetylcholine and bradykinin (P < 0.05). These effects were specific because smokeless tobacco extract had no significant effects on vasodilation elicited by nitroglycerin, an endothelium-independent agonist. Indomethacin, a cyclooxygenase inhibitor, and SQ-29548, a thromboxane A2/prostaglandin H2-receptor antagonist, abrogated the attenuating effects of smokeless tobacco extract on acetylcholine- and bradykinin-induced vasodilation. These data indicate that an aqueous extract of smokeless tobacco impairs endothelium-dependent vasodilation in the oral mucosa in situ in a specific fashion and that these effects are mediated, in part, by cyclooxygenase products of arachidonic acid metabolism that stimulate thromboxane A2/prostaglandin H2 receptors.
本研究的目的是确定无烟烟草（湿鼻烟）的水提取物是否能调节口腔黏膜原位的血管运动张力，如果可以调节，还要确定介导这些反应的机制。通过活体显微镜观察，我们发现该提取物对仓鼠颊囊阻力（二级）小动脉的直径[44±5（标准差）微米]没有显著影响。然而，它能显著减弱由两种内皮依赖性激动剂乙酰胆碱和缓激肽引起的血管舒张（P<0.05）。这些作用具有特异性，因为无烟烟草提取物对由内皮非依赖性激动剂硝酸甘油引起的血管舒张没有显著影响。环氧化酶抑制剂吲哚美辛和血栓素A2/前列腺素H2受体拮抗剂SQ-29548消除了无烟烟草提取物对乙酰胆碱和缓激肽诱导的血管舒张的减弱作用。这些数据表明，无烟烟草的水提取物以一种特定的方式损害口腔黏膜原位的内皮依赖性血管舒张，并且这些作用部分是由刺激血栓素A2/前列腺素H2受体的花生四烯酸代谢的环氧化酶产物介导的。
