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目的 探讨人逼尿肌中肾上腺素能 β受体反应性及G蛋白年龄相关性变化。 方法 采用细胞功能试验检测 10例老年人逼尿肌标本对 β受体激动剂BRL37344、腺苷酸环化酶激活剂For skolin和二丁基环腺苷酸 (DBcAMP)的反应 ,观察百日咳毒素 (PTX)和霍乱毒素 (CTX)对 β受体激动剂作用的影响 ;用 [3H] 双氢心得舒进行 β受体放射配基结合试验 ;检测Gsα 和Giα 含量。 结果 老年人逼尿肌细胞对KCl的收缩反应无明显改变 ,对异丙肾上腺素、BRL37344、Forskolin的松弛反应分别下降 15 .0 %、17.6 %和 12 .6 %(P <0 .0 0 1) ,对DBcAMP的反应与对照组差异无显著性意义 ;异丙肾上腺素和BRL37344的pD2 显著降低 ,但PTX可以显著提高二者的松弛作用 ,CTX对其无明显影响 ;β受体的最大结合部位显著减少 ,平衡解离常数无明显变化 ;老年人逼尿肌Giα 含量增加了 45 .8%(P <0 .0 5 ) ,Gsα 含量无明显变化。 结论 老年人逼尿肌中 β受体反应性下降可能是膀胱顺应性减退的原因 ,受体密度以及腺苷酸环化酶活性下降以及Giα 含量增加可能是β受体反应性降低的分子机制。
Objective To investigate the adrenergic β receptor reactivity and the age-related changes of G protein in human detrusor muscle. Methods The cell function test was used to detect the reaction of β receptor agonist BRL37344, adenylyl cyclase activator For skolin and DBcAMP in 10 elderly detrusor specimens. The levels of pertussis toxin (PTX) And cholera toxin (CTX) on the effect of β receptor agonist; [3H] dihydrochloride was Shu for β receptor radioligand binding assay; detection Gsα and Giα content. Results The elderly patients detrusor myocytes did not show any significant changes in the contractile response to KCl. The relaxation responses to isoproterenol, BRL37344 and Forskolin decreased by 15.0%, 17.6% and 12.6% (P <0. ), The response to DBcAMP was not significantly different from that of the control group. The isoproterenol and BRL37344 pD2 significantly decreased, but PTX can significantly improve the relaxation of both, CTX had no significant effect; the maximum binding of β receptor And the equilibrium dissociation constant had no significant changes. The content of Giα in elderly detrusor muscle increased by 45.8% (P <0.05), while the content of Gsα did not change significantly. Conclusions The decline of β receptor reactivity in the detrusor of elderly may be the cause of bladder compliance. The decrease of receptor density and adenylyl cyclase activity and the increase of Giα may be the molecular mechanism of β receptor reactivity decrease.