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目的:研究雌二醇对离体和在体气管平滑肌收缩的作用.方法:(1)将家兔离体气管平滑肌条置于装有Krebs液的肌槽中温育,并通入95％O_2和5％CO_2的混合气体.二导记录仪记录肌条的等长张力.(2)测量肌注雌二醇(1mg/kg)前后乙酰胆碱和组胺引发豚鼠哮喘的潜伏期.结果:(1)雌二醇(100μmol/L)对乙酰胆碱和氯化钾诱发的收缩有明显的舒张作用(舒张百分比分别为39％±5％和45％±19％).其作用可被蚓哚美辛和亚甲蓝部分阻断(26％±8％和28％±13％),但不能被L-NNA、心得安和去除上皮所影响(舒张百分比分别为38％±10％,40％±15％,37％±8％).雌二醇能使乙酰胆碱及氯化钙的量效曲线明显右移(pD_2~′值分别为3.98和4.75).另外,雌二醇可明显抑制乙酰胆碱引起的第Ⅰ时相性收缩,对氯化钙引起的第Ⅱ时相性的收缩无明显影响.(2)肌注雌二醇(1mg/kg)可使豚鼠的引喘潜伏期明显延长.结论:(1)雌二醇对兔离体气管平滑肌的作用是非上皮依赖性的,与抑制电压依赖性钙通道和细胞内钙从内质网的释放有关,还部分与cGMP介导的松弛途径及刺激气道平滑肌释放前列腺素类物质有关,但与β-肾上腺素能受体介导的舒张无关.(2)雌二醇可明显舒张豚鼠在体气管平滑肌.
OBJECTIVE: To study the effect of estradiol on contraction of isolated and tracheal smooth muscle.Methods: (1) Rabbit tracheal smooth muscle strips were incubated in muscle chamber containing Krebs fluid and infused with 95% O2 and 5% CO 2 gas mixture.The two-way recorder recorded the isometric tension of muscle strips. (2) The latency of asthma induced by acetylcholine and histamine before and after intramuscular injection of estradiol (1mg / kg) were measured.Results: (1) Diol (100 μmol / L) significantly attenuated acetylcholine and potassium chloride-induced contractions (diastolic percentage of 39% ± 5% and 45% ± 19%, respectively) The blue fraction was blocked (26% ± 8% and 28% ± 13%) but not by L-NNA, propranolol, and removal of the epithelium (diastolic percentages were 38% ± 10%, 40% ± 15%, 37 % ± 8%). Estradiol significantly shifted the dose-response curves of acetylcholine and calcium chloride to the right (pD_2 ~ 3.98 and 4.75, respectively). In addition, estradiol significantly inhibited the phase Ⅰ activity induced by acetylcholine (2) Intramuscular injection of estradiol (1 mg / kg) significantly prolonged the period of asthma induction in guinea pigs.Conclusion: (1) Estradiol The effect on isolated tracheal smooth muscle in rabbits is non-epithelial dependent, and is related to the inhibition of voltage-dependent calcium channels and intracellular calcium release from the endoplasmic reticulum, and partly to the cGMP-mediated relaxation pathway and stimulation of airway smooth muscle release of prostaglandins But not with β-adrenergic receptor-mediated relaxation. (2) Estradiol obviously relieved guinea pig tracheal smooth muscle.