ANESTHETIC DEPRESSION OF THE MYOCARDIUM

在患者中观察到低血压和心脏骤停 用麻醉剂氟烷、恩氟烷和异氟烷麻醉。 这些挥发性麻醉剂（VA）目前在临床上广泛使用。 初步证据表明，VA可能会降低可用性 心脏收缩所需的Ca 2+。该项目旨在 研究上述麻醉剂对结构的影响， 心肌细胞调节Ca 2+流量，控制心肌细胞内Ca 2+浓度， 收缩。将要研究的元素是：肌膜（SL）， 肌细胞的外膜;肌浆网（SR）， 控制肌浆Ca 2+量的膜网络;和 肌钙蛋白（Tn）是一种通过改变其 形成并启动收缩过程。实验也将 在分离的乳头肌、肌细胞和完整动物上进行， 将发现的结果与孤立的亚细胞结构相结合， 更复杂的生理系统。现有证据表明， SR和SL受麻醉剂的影响，可能是主要的 收缩力的改变。这些研究概述了 氟烷、安氟醚和异氟醚与亚细胞 结构以观察CA 2+反应的改变。结果将 量化每种麻醉剂对每种结构的相对影响， 可能的作用机制将被假定。获得的数据将 帮助制定药物干预措施，以防止麻醉- 在手术室里引起了心脏抑制

Hypotension and cardiac arrest have been observed in patients anesthetized with the anesthetics halothane, enflurane, and isoflurane. These volatile anesthetics (VA) are in wide clinical use today. Preliminary evidence suggests that the VA might decrease the availability of Ca2+ required for cardiac contraction. This project is designed to study the effect of the above mentioned anesthetics on structures in the myocardial cell that regulate Ca2+ flux and control the intensity of contraction. The elements that will be studied are: the sarcolemma (SL), the outer membrane of the muscle cell; the sarcoplasmic reticulum (SR), a membranous network that controls the amount of myoplasmic Ca2+; and troponin (Tn), a protein that responds to Ca2+ binding by changing its shape and initiating the contractile process. Experiments will also be performed on isolated papillary muscles, myocytes and intact animals to integrate the results found with the isolated subcellular structures with systems of more physiological complexity. Present evidence suggest that the SR and SL are affected by anesthetics and may be the major sites of alteration of contractility. The studies outlined with examine the interaction of halothane, enflurane, and isoflurane with the subcellular structures to observe alteration in CA2+ response. The results will quantify the relative effect of each anesthetic on each structure and a possible mechanism of action will be postulated. The data obtained will help in formulating pharmacologic interventions to prevent anesthetic- induced cardiac depression in the operating room.