一氧化氮(NO)是由L-精氨酸通过一氧化氮合酶(NOS)合成,是一种已知的来源于内皮细胞的松弛因子,在整个妊娠期间由于雌激素和绒毛膜促性腺激素激活NOS表达,从而血浆内NO水平升高,并对控制妊娠期子宫肌静止状态及血管张力起重要作用。但NO导致子宫肌松弛的机制仍不清楚。作者从孕足月行选择性子宫下段剖宫产妇女的子宫切口上缘取10mm~3子宫肌层,去除内膜和结缔组织,切成小块,用无钙无镁的Hank’s平衡盐溶液清洗,用Ⅲ型胶原酶在37℃孵育90 min使小块组织分散成单个平滑肌细胞。这些单细胞用含10％小牛血清的Dulbecco’s改良Eagle’s培养基,在培养皿底部放置盖玻片,密度10~(-5)～10~(-6)细胞/ml,5％CO_2,37℃培养7～10 d后,细胞用脂多糖(LPS)培养6 h以上进行预处理。将软玻璃片滴管制作成电极,电阻为5～7MΩ做单通道记录,将培养好细胞的盖玻片放在实验溶液内 Nitric oxide (NO), synthesized from L-arginine by nitric oxide synthase (NOS), is a known endothelial cell-derived relaxing factor that is secreted by estrogen and chorionic gonadotropin Hormone activation of NOS expression, thereby increasing the plasma level of NO, and to control the resting state of uterine muscle during pregnancy and vascular tone play an important role. However, the mechanism by which NO causes uterine muscle relaxation remains unclear. The author fetches 10mm ~ 3 myometrium from the upper edge of the uterine incision of pregnant woman with full-term selective cesarean section, removes the intima and connective tissue, cuts it into small pieces, and cleans it with Hank’s balanced salt solution without calcium and magnesium , With type Ⅲ collagenase incubated at 37 ℃ for 90 min to small pieces of tissue dispersed into single smooth muscle cells. The single cells were fixed in Dulbecco’s modified Eagle’s medium containing 10% fetal bovine serum, and the coverslips were placed on the bottom of the culture dish at a density of 10 -5 to 10 -6 cells / ml, 5% CO 2, 37 ° C. After cultured for 7-10 days, the cells were pretreated with lipopolysaccharide (LPS) for more than 6 h. The soft glass dropper made into an electrode, the resistance of 5 ~ 7MΩ to do single-channel recording, the well-cultured cell cover glass slide in the experimental solution