吸入性麻醉药对骨骼肌钙离子通道RyR1影响的实验研究

It is identified by clinical observational studies that inhaled anesthetics have influences on relaxation of skeletal muscle, but how this occur is not clear. In our preliminary studies, we found that inhaled anesthetics trigger aberrant Ca2+ release through type 1 ryanodine receptors (RyR1) in skeletal muscle of malignant hyperthermia (MH) susceptibility and a potentially fatal rise in perioperative body temperature. It is also showed that inhaled anesthetics can relax tracheal smooth muscle by increasing the calcium ion "leaking" through RyR. Therefore, we hypothesize that inhaled anesthetics directly affect normal skeletal muscle, cause RyR1-mediated Ca2+ slow release from SR, lead to normal skeletal muscle relaxation. In the current proposal, we will divide the experimental miniature pigs and pietrain swines into RyR1 normal or abnormal groups by RyR1 gene detection. Then, we use in vitro contraction test (IVCT) to observe the effect of inhaled anesthetics on skeletal muscle contraction tension without the influence of the central nervous system. Finally, we use patch clamp techniques to study the effect of inhaled anesthetics on RyR1 calcium release channels. This proposed study will improve our understandings of how inhaled anesthetics directly affect the skeletal muscle cells.

临床观察性研究表明，吸入性麻醉药有骨骼肌松弛作用，但是否对骨骼肌细胞直接产生作用尚不明确。我们前期研究证明对于RyR1异常的恶性高热易感者，吸入性麻醉药诱导RyR1出现Ca2+瞬时大量释放，导致骨骼肌强直收缩，出现致死率极高的恶性高热。同时研究表明吸入性麻醉药舒张气管平滑肌的作用机制是通过作用RyR，提高受体通道钙的"渗漏"。据此我们推测，吸入性麻醉药对正常骨骼肌的松弛作用，可能通过影响骨骼肌细胞RyR1，导致Ca2+少量缓慢释放所致。本项目拟选用RyR1异常的皮特兰猪和正常的实验小型猪，通过基因检测分为RyR1正常组和RyR1异常组，首先进行骨骼肌体外收缩试验（IVCT），研究在排除中枢神经系统的影响的情况下，吸入性麻醉药对正常/异常钙离子通道的骨骼肌收缩张力的影响。然后利用膜片钳技术，在细胞水平研究吸入性麻醉药对RyR1钙离子释放的影响。试图阐明吸入性麻醉药对骨骼肌细胞直接作用的机制。

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