【摘要】 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％O₂和5％CO₂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（pD₂^′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.更多还原

【Abstract】 To investigate the effect of β-estradiol on trachea smooth muscle contraction in vitro and in vivo. METHODS: (1) Rabbit tracheas were incubated in organ baths filled with Krebs solution and supplied with a mixed gas of 95 % O2 and 5 % CO2. The isometric force was measured by ink-writing recorders. (2) The incubation period of asthma induced by histamine and acetylcholine (ACh) in guinea pig were measured before and after β-estradiol ( 1 mg/kg ) were given intramuscularly. RESULTS: (1) Administration of β-estradiol (0.1 mmol/L) caused relaxation of isolated trachea muscle strips (TMS) in rabbits pre-contracted by ACh and KC1 (39 %± 5 % and 45 %±19 % ). The presence of indomethacin or methylene blue partly decreased the relaxation to β-estradiol (26% ±8 % and 28%±13%), but N-nitro-L-arginine (L-NNA) and propranolol and epithelium removal did not affect it (38 %±10 % , 40 %±15 % , 37 %±8%).β-Estradiol can shifted the concentration-response curves of ACh and CaCl2 to the rightward (pD2=3.98 and 4.75). In addition, it could also significantly inhibit the contraction of phase Ⅰ caused by ACh, but did not affect the contraction of phase Ⅱ caused by CaCl2. (2) The incubation period of asthma in guinea pig were delayed by β-estradiol (1 mg/kg ) given intramuscularly. CONCLUSION: (1) The relaxation of β-estradiol in vitro was epithelium independent and associated with the inhibition of potential-dependent channel and release of Ca2+ from sarcoplasm reticulum induced by ACh. In addition, release of prostaglandins from trachea smoothmuscle cells and relaxation through cGMP approach were also included.β-Adrenoceptor-mediated relaxation was not involved. ( 2 )β-Estradiol can relax the trachea in vivo in guniea pig.更多还原