摘要
目的:观察不同月龄大鼠空肠平滑肌对β受体激动剂异丙肾上腺素(Iso)反应性的变化,初步探讨其变化的机制.方法:采用灌流法加药,利用张力换能器记录离体空肠平滑肌张力的变化.结果:20月龄组大鼠空肠平滑肌收缩频率都低于3月龄组(27.0±2.5vs30±3.1,P<0.05);灌流10-9-10-6mol/L终浓度的Iso后,20月龄组大鼠空肠平滑肌收缩幅度变化的百分率(即舒张反应)都低于3月龄组(3×10-8,-41.4%,P<0.05;1×10-7,-34.6%,P<0.05;3×10-7,-25.0%,P<0.05;1×10-6,-19.5%,P<0.05);加Nω-nitro-L-arginine(L-NNA)后,3月龄组对Iso的舒张反应降低,而20月龄组对IsO的舒张反应未见明显变化;抑制NOS前,20月龄组Iso的pD2值比3月龄组的pD2值小(6.52±0.54vs6.98±0.3,P<0.05).结论:大龄大鼠空肠平滑肌对Iso的反应性下降;NOS或一氧化氮(NO)的作用降低可能是引起大龄大鼠空肠平滑肌对Iso的反应性下降的重要原因之一.
AIM： To investigate the response of jejunal smooth muscles （JSMs） to nonselective β-adrenoceptor agonist （Isoproterenol, Iso） in rats with different ages and its possible mechanism. METHODS： The nonselective β-adrenoceptor agonist Iso and nonselective nitric oxide synthase （NOS） inhibitor N^（1）nitro -L-arginine （L-NNA） were perfused into the baths of rat JSMs. Muscle force transducer （MFT） was used to measure the tension of JSMs. RESULTS： The contractive frequency of JSMs was markedly lower in 20-month rats than that in 3-month rats （27.0±2.5 vs30±3 1, P〈0. 05）After perfusion with Iso （Final concentration： 1 x 10^-9-1 x 10^-6 mol/L）, the variation rates of contractive amplitude of JSMs in 20-month rats were lower than those in 3-month rats （3 x 10.^-8 mol/L： -41.4%, P〈0.05; 1 x 10^-7 mol/L： -34.6%, P〈0.05; 3 x 10^-7 mol/L： -25.0%, P〈0.05; 1 X 10^-6 mol/L： -19.5%, P〈0.05）. After the administration of L-NNA, the relaxation responses of JSMs decreased in 3-month rats, while there was no obvious variation in 20-month rats. Before the administration of L-NNA, the pD2 of β-adrenoceptor decreased in 20-month rats as compared with that in 3-month rats （6.52 4± 0.54 vs 6.98± 0.30, P〈0.05）. CONCLUSION： The response of JSMs to Iso in aged rats decreases, and the mechanism may be related to the decreased effect of NOS or nitric oxide.
出处
《世界华人消化杂志》
CAS
北大核心
2005年第15期1852-1855,共4页
World Chinese Journal of Digestology
