Kato T, Bishop A T, Wood M B
Department of Orthopedics, Mayo Clinic, Rochester, MN 55905, USA.
J Orthop Res. 1996 Nov;14(6):956-61. doi: 10.1002/jor.1100140616.
The effect of human adrenomedullin was investigated using an ex vivo perfused canine tibial model in the absence of vascular endothelium. Adrenomedullin is a novel peptide with known vasodilator properties. In this model, a 0.1 ml bolus injection of 10(-5) M of either acetylcholine or adrenomedullin decreased vascular resistance in tibial preparations precontracted with prostaglandin F2 alpha by 88.3 +/- 3.0% and 92.8 +/- 2.8%, respectively, in the presence of vascular endothelium. Conversely, a 0.1 ml bolus injection of 10(-5) M acetylcholine produced a constrictor response after removal of vascular endothelium. A 0.1 ml bolus injection of 10(-5) M adrenomedullin decreased the baseline perfusion pressure in a dose-dependent manner for a duration of 20 minutes and also attenuated the pressor response to exogenous norepinephrine injection for at least 10 minutes compared with the control study (p < 0.05) in the absence of vascular endothelium. These data suggest that human adrenomedullin relaxes blood vessels in bone by a direct action on vascular smooth-muscle cells. In addition, the attenuation effect of human adrenomedullin on pressor responses to exogenous norepinephrine injection is independent of vascular endothelium.
在无血管内皮的情况下，使用离体灌注犬胫骨模型研究了人肾上腺髓质素的作用。肾上腺髓质素是一种具有已知血管舒张特性的新型肽。在该模型中，在有血管内皮存在时，0.1 ml推注10(-5)M的乙酰胆碱或肾上腺髓质素，分别使预先用前列腺素F2α预收缩的胫骨制剂中的血管阻力降低了88.3±3.0%和92.8±2.8%。相反，在去除血管内皮后，0.1 ml推注10(-5)M乙酰胆碱产生了收缩反应。在无血管内皮的情况下，0.1 ml推注10(-5)M肾上腺髓质素以剂量依赖的方式使基线灌注压力降低20分钟，并与对照研究相比，对外源性去甲肾上腺素注射的升压反应至少减弱10分钟（p<0.05）。这些数据表明，人肾上腺髓质素通过直接作用于血管平滑肌细胞使骨血管舒张。此外，人肾上腺髓质素对外源性去甲肾上腺素注射升压反应的减弱作用与血管内皮无关。
