Park K W, Dai H B, Lowenstein E, Sellke F W
Department of Anesthesia and Critical Care, Beth Israel Hospital, Harvard Medical School, Boston, Massachusetts 02215, USA.
Anesth Analg. 1996 May;82(5):969-74. doi: 10.1097/00000539-199605000-00014.
The myogenic response of vascular smooth muscle produces vasomotion in response to changes in vessel transmural pressure. While this is an important determinant of coronary blood distribution, the effect of volatile anesthetics on the response has not been previously investigated. In this study, we examined the effect of isoflurane and halothane on this myogenic response. Coronary resistance arteries were isolated from Wistar rats. As the intraluminal pressure was increased from 10 to 120 mm Hg in the presence of either isoflurane (1%, 2%, and 3%), halothane (1% and 2%), or no volatile agent (control), the vessel intraluminal diameter was monitored using a video detection system. Passive changes in vessel diameter were measured after exposure to papaverine 100 microM. Additionally, the myogenic responses of endothelium-intact and endothelium-denuded vessels were compared. Endothelium-intact control vessels demonstrated myogenic constriction above 80 mm Hg of intraluminal pressure. This response was not affected by endothelial denudation. The response was preserved by isoflurane 1%, 2% or 3% but abolished by halothane 1% or 2%. We conclude that, in rat coronary resistance arteries, myogenic constriction can be demonstrated above 80 mm Hg of intraluminal pressure and is endothelium independent. This response is preserved by isoflurane but abolished by halothane. These findings may have implications for the effect of the anesthetics on coronary blood flow distribution.
血管平滑肌的肌源性反应会根据血管跨壁压力的变化产生血管运动。虽然这是冠状动脉血液分布的一个重要决定因素，但挥发性麻醉剂对该反应的影响此前尚未得到研究。在本研究中，我们检测了异氟烷和氟烷对这种肌源性反应的影响。从Wistar大鼠分离出冠状动脉阻力动脉。当在存在异氟烷（1%、2%和3%）、氟烷（1%和2%）或无挥发性药物（对照）的情况下，将管腔内压力从10 mmHg升高至120 mmHg时，使用视频检测系统监测血管管腔直径。在暴露于100 microM罂粟碱后测量血管直径的被动变化。此外，还比较了内皮完整和内皮剥脱血管的肌源性反应。内皮完整的对照血管在管腔内压力高于80 mmHg时表现出肌源性收缩。这种反应不受内皮剥脱的影响。1%、2%或3%的异氟烷可保留该反应，但1%或2%的氟烷可消除该反应。我们得出结论，在大鼠冠状动脉阻力动脉中，在管腔内压力高于80 mmHg时可表现出肌源性收缩，且不依赖于内皮。这种反应可被异氟烷保留，但被氟烷消除。这些发现可能对麻醉剂对冠状动脉血流分布的影响具有启示意义。
