Regulation of vascular tone by endothelium, nerve and blood cells through their reciprocal actions.

我们研究了缺氧或酸中毒时内皮、外膜（神经）和血细胞（白细胞：WBC）对血管张力的影响。缺氧使血管收缩。内皮的去除可减弱缺氧引起的血管收缩。环氧化酶抑制剂可减弱缺氧引起的血管收缩，提示环氧化酶相关的二十烷类化合物可能在缺氧时从内皮中释放。相反，去除内皮和外膜可消除缺氧引起的收缩。这些发现提示外膜和内皮可能参与了缺氧引起的收缩。研究还发现，酸中毒以不同的方式减弱激动剂诱导的收缩，这取决于所使用的激动剂的类型，内皮促进酸中毒对激动剂诱导的收缩的减弱作用。从白细胞对血管张力影响的实验中，我们发现白细胞通过内皮间接扩张血管平滑肌。我们用几种拮抗剂研究了内皮细胞释放的物质。然而，我们无法检测到这种物质。有报道称，对内皮细胞施加剪切应力可释放内皮源性松弛物质。将这些现象应用到人体内皮功能的研究中，我们发现内皮在某些疾病中起不到很好的作用。综上所述，我们发现内皮、外膜和血管通过相互作用调节血管张力。

We investigated the effects of endothelium, adventitia (nerve), and blood cells(white blood cells : WBC) on vascular tone during hypoxia or acidosis. Hypoxia contracted blood vessels. Removal of endothelium attenuated the hypoxia-induced contraction of blood vessels. Cyclooxygenase inhibitors attenuated the hypoxia-induced contraction of blood vessels, suggesting that cyclooxygenase related eicosanoids may be released from endothlium during hypoxia. In contrast, removal of endothlium and adventitia abolished the hypoxia-induced contraction. These findings syggest that adventitia as well as endothlium may contribute to the hypoxia-induced contraction. It was also found that acidosis attnuated the agonist-induced contraction in a different manner depending the type of agonists used, and that endothelium facilitated the attenuated action of acidosis on agonist-induced contraction. From the experiment concerning the effect of WBC on vascular tone, we found that WBC dilates vascular smooth muscle indirectly through endothlium. We investigated the substance released from endothelium using some kinds of antagonists. However, we could not detect the substance. It has been reported that shear stress on endothelium releases endothlium-derived relaxing substance(s). Applying these phenomenon to research in testing human endothelial function, we found that endothelium did not work well in some kind of disease. In summary we found that endothelium, adventitia and blood vessels regulate vascular tone through their reciprocal actions.