Conde M V, Marco E J, Fraile M L, Benito J M, Moreno M J, Sanz M L, López de Pablo A L
Departamento de Fisiología, Facultad de Medicina, Universidad Autónoma, Madrid, Spain.
J Pharm Pharmacol. 1991 Apr;43(4):255-61. doi: 10.1111/j.2042-7158.1991.tb06679.x.
The present work was undertaken to elucidate the role of the vascular endothelium in the changes of isometric tension elicited by different compounds in isolated cylinders of human and cat cerebral arteries and cat pulmonary arteries. Endothelium removal by rubbing significantly reduced the relaxing response to acetylcholine (ACh) of isolated segments of all the arteries. The same treatment did not modify the contraction elicited by 5-hydroxytryptamine (5-HT) in the human and cat cerebral segments but increased the contractile effect of the amine in cat pulmonary arteries. The mechanical responses to vasopressin, ATP and adenosine in isolated segments of cat cerebral arteries were unaffected after removing the endothelial layer. L-Arginine, but not D-arginine (10(-5) M), enhanced significantly the relaxation induced by increasing doses of ACh in unrubbed cat cerebral arteries whereas it did not modify the response to ACh in rubbed ones. However, L-arginine had no effect on the dose-response curve to 5-HT in both kinds of preparation and did not change the tone in precontracted unrubbed cat cerebral segments. These results suggest that the endothelium of the cerebrovascular bed plays a minor role in regulating the mechanical response induced by several vasoactive agents, although it retains its ability to produce an endothelium-derived relaxing factor.
本研究旨在阐明血管内皮在人及猫脑动脉和猫肺动脉离体血管条中，不同化合物引起的等长张力变化中的作用。通过摩擦去除内皮显著降低了所有动脉离体节段对乙酰胆碱（ACh）的舒张反应。相同处理并未改变人及猫脑动脉节段对5-羟色胺（5-HT）的收缩反应，但增强了该胺对猫肺动脉的收缩作用。去除猫脑动脉离体节段的内皮后，其对血管加压素、ATP和腺苷的机械反应未受影响。L-精氨酸（而非D-精氨酸，10(-5) M）显著增强了未摩擦的猫脑动脉中递增剂量ACh诱导的舒张，而对摩擦后的动脉中ACh的反应无影响。然而，L-精氨酸对两种制剂中5-HT的剂量反应曲线均无影响，且未改变预收缩的未摩擦猫脑动脉节段的张力。这些结果表明，脑血管床的内皮在调节几种血管活性物质诱导的机械反应中起次要作用，尽管它保留了产生内皮源性舒张因子的能力。
