Region-specific and agent-specific dilation of intracerebral microvessels by volatile anesthetics in rat brain slices
Region-specific and agent-specific dilation of intracerebral microvessels by volatile anesthetics in rat brain slices
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DOI：
10.1097/00000542-199711000-00024
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发表时间：
1997-11-01
期刊：
影响因子：
8.8
通讯作者：
Schmeling, WT
中科院分区：
文献类型：
--
作者：
Farber, NE;Harkin, CP;Schmeling, WT
背景：挥发性麻醉剂是有效的脑血管扩张剂。虽然脑血管阻力的主要部位是脑内小动脉，但没有研究比较挥发性麻醉剂对脑实质微血管的作用。作者比较了氟烷和异氟烷对海马和新皮层微血管脑内小动脉反应性的影响。方法：经机构审查委员会批准，将麻醉后的sd大鼠海马或新皮质脑切片置于灌注记录室，灌注人工脑脊液。在灌注液中平衡氟烷或异氟烷之前、期间和之后，用视频显微镜监测动脉直径。PGF（2 α）在麻醉前预缩血管，盲眼观察者使用计算机视频测微仪分析直径变化。各组间微血管基线直径和预缩程度无差异。在海马中，挥发性药物在氟烷和异氟醚作用下产生的浓度依赖性扩张（以预缩对照+/- SEM的百分比表示）分别为68 +/- 6%和79 +/- 9% (1 MAC)， 120 +/- 3%和109 +/- 5% (2 MAC) （P < 0.05）。异氟烷引起的血管舒张明显小于相似MAC水平的氟烷（1 MAC时84 +/- 9% vs 42 +/- 5%； 2 MAC时氟烷vs异氟烷分别为121 +/- 4% vs 83 +/- 5%）。结论：氟烷与异氟烷对脑实质内微血管的剂量依赖性扩张作用存在差异。这些发现表明，挥发性麻醉药对脑内微血管直径的局部影响显著有助于脑血管阻力的改变，并支持先前描述的这些药物对脑血流的异质作用。
Background: Volatile anesthetics are potent cerebral vasodilators. Although the predominant site of cerebrovascular resistance is attributed to intracerebral arterioles, no studies have compared the actions of volatile anesthetics on intraparenchymal microvessels. The authors compared the effects of halothane and isoflurane on intracerebral arteriolar responsiveness in hippocampal and neocortical microvessels using a brain slice preparation.Method: After Institutional Review Board approval, hippocampal or neocortical brain slices were prepared from anesthetized Sprague-Dawley rats and placed in a perfusion-recording chamber, superfused with artificial cerebrospinal fluid. Arteriolar diameters were monitored with videomicroscopy before, during, and after halothane or isoflurane were equilibrated in the perfusate. PGF(2 alpha) preconstricted vessels before anesthetic administration, A blinded observer using a computerized videomicrometer analyzed diameter changes,Results: Baseline microvessel diameter and the degree of preconstriction were not different between groups, In the hippocampus, the volatile agents produced similar, concentration-dependent dilation (expressed as percent of preconstricted control +/- SEM) of 68 +/- 6% and 79 +/- 9% (1 MAC) and 120 +/- 3% and 109 +/- 5% (2 MAC) (P < 0.05) during halothane and isoflurane, respectively, In the cerebral cortex, isoflurane caused significantly less vasodilation than did similar MAC levels of halothane (84 +/- 9% vs. 42 +/- 5% dilation at 1 MAC; 121 +/- 4% vs. 83 +/- 5% dilation at 2 MAC halothane vs. isoflurane, respectively).Conclusion: Halothane and isoflurane differentially produce dose-dependent dilation of intraparenchymal cerebral microvessels. These findings suggest that local effects of the volatile anesthetics on intracerebral microvessel diameter contribute significantly to alterations in cerebrovascular resistance and support previously described heterogeneous actions on cerebral blood flow produced by these agents.