Scotland R, Vallance P, Ahluwalia A
Centre for Clinical Pharmacology, Wolfson Institute of Biomedical Research, University College London, Rayne Institute, London, UK.
Cardiovasc Res. 1999 Jan;41(1):237-45. doi: 10.1016/s0008-6363(98)00223-5.
The vasa vasorum form a network of microvessels in and around the walls of large blood vessels and are thought to be necessary to delivery oxygenated blood to the outer parts of the vessel wall that are inadequately nourished by diffusion from luminal blood. This study was undertaken to investigate directly the mechanisms which control tone in the vasa vasorum.
Arterial vasa vasorum were dissected from the walls of porcine or bovine thoracic aorta and mounted in a tension myograph. Concentration-response curves were constructed to vasoconstrictors; endothelin-1(ET-1), noradrenaline (NA) angiotensin II (Ang II) and thromboxane A2-mimetics (U44069 or U46619) or vasodilators; substance P (SP) bradykinin (BK), calcitonin gene-related peptide (CGRP) or isoprenaline. Strips of porcine aorta were mounted in 25 ml organ baths.
Potent concentration-dependent contraction of vasa vasorum was produced by ET-1. NA was a weak constrictor, Ang II had no effect or produced contraction that underwent tachyphylaxis and thromboxane A2-mimetics had no effect. In contrast NA, Ang II, U-44069 and ET-1 all produced potent concentration-dependent contraction of aortic strips. SP and BK produced endothelium-dependent relaxation while CGRP produced endothelium-independent relaxation of ET-1-precontracted vasa vasorum. Isoprenaline had no relaxant effect.
We have demonstrated functional responses of arterial vasa vasorum to vasodilators and vasoconstrictors. Additionally these microvessels appear to respond to constrictors differently from the large host vessel.
血管滋养血管在大血管壁内及周围形成微血管网络，被认为对于将含氧血液输送到血管壁外层是必要的，因为从管腔内血液扩散来的营养物质无法充分滋养这些部位。本研究旨在直接探究控制血管滋养血管张力的机制。
从猪或牛的胸主动脉壁上分离出动脉血管滋养血管，并安装在张力肌动描记器中。构建血管收缩剂（内皮素-1（ET-1）、去甲肾上腺素（NA）、血管紧张素II（Ang II）和血栓素A2模拟物（U44069或U46619））或血管舒张剂（P物质（SP）、缓激肽（BK）、降钙素基因相关肽（CGRP）或异丙肾上腺素）的浓度-反应曲线。将猪主动脉条安装在25毫升器官浴槽中。
ET-1可使血管滋养血管产生强烈的浓度依赖性收缩。NA是一种较弱的收缩剂，Ang II无作用或产生快速耐受的收缩，血栓素A2模拟物无作用。相比之下，NA、Ang II、U-44069和ET-1均可使主动脉条产生强烈的浓度依赖性收缩。SP和BK产生内皮依赖性舒张，而CGRP可使ET-1预收缩的血管滋养血管产生非内皮依赖性舒张。异丙肾上腺素无舒张作用。
我们已证明动脉血管滋养血管对血管舒张剂和血管收缩剂的功能反应。此外，这些微血管对收缩剂的反应似乎与大的宿主血管不同。
