Enhanced myogenic tone in cerebral arteries from a rabbit model of subarachnoid hemorrhage
Enhanced myogenic tone in cerebral arteries from a rabbit model of subarachnoid hemorrhage
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DOI：
10.1152/ajpheart.00629.2002
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发表时间：
2002-12-01
影响因子：
4.8
通讯作者：
Wellman, GC
中科院分区：
文献类型：
--
作者：
Ishiguro, M;Puryear, CB;Wellman, GC
脑动脉血管痉挛。是蛛网膜下腔出血 (SAH) 患者死亡和残疾的主要原因。目前，关于SAH对小直径（100-200μm）脑动脉的影响知之甚少，而小直径脑动脉在脑血流的自动调节中发挥着重要作用。通过使用兔 SAH 模型和体外视频显微镜，测量了血管内压力升高时的脑动脉直径。与对照或假手术动物相比，SAH 动物的脑动脉在 60-100 mmHg 生理范围内的压力收缩更多（接近两倍）。在氧合血红蛋白存在下培养的对照动物器官中，压力诱导的收缩（肌源性张力）也得到增强，这是一种独立于血管内皮的效应。或一氧化氮合成。最后，当血管内压力升高到 140 mmHg 以上时，对照动物和 SAH 动物的动脉都扩张。这项研究为 SAH 期间氧合血红蛋白在小直径脑动脉自身调节受损（即肌源性张力增强）中的作用提供了证据。此外，改善 SAH 患者临床结果的治疗策略（例如超生理血管内压）可有效扩张从 SAH 动物分离的小直径脑动脉。
Cerebral artery vasospasm. is a major cause of death and disability in patients experiencing subarachnoid hemorrhage (SAH). Currently, little is known regarding the impact of SAH on small diameter (100-200 mum) cerebral arteries, which play an important role in the autoregulation of cerebral blood flow. With the use of a rabbit SAH model and in vitro video microscopy, cerebral artery diameter was measured in response to elevations in intravascular pressure. Cerebral arteries from SAH animals constricted more (similar totwo-fold) to pressure within the physiological range of 60-100 mmHg compared with control or sham-operated animals. Pressure-induced constriction (myogenic tone) was also enhanced in arteries from control animals organ cultured in the presence of oxyhemoglobin, an effect independent of the vascular endothelium. or nitric oxide synthesis. Finally, arteries from both control and SAH animals dilated as intravascular pressure was elevated above 140 mmHg. This study provides evidence for a role of oxyhemoglobin in impaired autoregulation (i.e., enhanced myogenic tone) in small diameter cerebral arteries during SAH. Furthermore, therapeutic strategies that improve clinical outcome in SAH patients (e.g., supraphysiological intravascular pressure) are effective in dilating small diameter cerebral arteries isolated from SAH animals.