Maturation of acetylcholinesterase expression in tracheal smooth muscle contraction.
Maturation of acetylcholinesterase expression in tracheal smooth muscle contraction.
复制标题
气管平滑肌收缩时乙酰胆碱酯酶表达的成熟。
DOI：
10.1152/ajplung.1990.259.2.l130
复制
发表时间：
1990
期刊：
影响因子：
--
通讯作者：
Leff,AR
中科院分区：
文献类型：
--
作者：
Mitchell,RW;Murphy,TM;Kelly,E;Leff,AR
我们研究了节后发育的乙酰胆碱酯酶（Achase）活性和气管平滑肌（TSM）收缩引起的拟胆碱激活和电场去极化在体外。从21只2周龄猪（2 ws）和19只10周龄猪（10 ws）中切下的上皮完整气管条以最佳静息长度等距拴系，反应表示为最大值对63 mM氯化钾（%KCl）的百分比。对于TSM，2周和10周时KCl的累积浓度-反应曲线相当。然而，2周时对ACh的最大收缩（168 +/-8.4%KCl）大于10周时的最大收缩（142 +/-2.3%KCl; P <0.02）。刺激-反应曲线（场电极; AC源）显示10周内TSM的敏感性更高（刺激引起50%的最大反应= 2周内3.32 +/- 0.13 V vs. 10周内2.25 +/- 0.12 V; P小于0.001），表明2周内更高的拟胆碱反应性不是由突触前神经传导增强引起的。乙酰胆碱酯酶抑制剂毒扁豆碱（physostigmine）使1）电场刺激引起的反应在2周内更敏感（P <0.05），但10周内无显著性差异（P = NS）; 2）10周内对外源性ACh的最大反应增强（27%增加; P小于0.01），但不是2 ws（2%增加; P = NS），和3）与10 ws相比，2 ws对拟胆碱激活的敏感性增加更大（P小于0.02）。这些数据表明，TSM在2周与10周内的胆碱能收缩增加，这至少部分是由于未成熟动物气管中Achase活性降低所致。
We examined postganglionic development of acetylcholinesterase (AChase) activity and tracheal smooth muscle (TSM) contraction elicited by cholinomimetic activation and electrical field depolarization in vitro. Epithelium-intact tracheal strips excised from 21 2-wk-old swine (2ws) and 19 10-wk-old swine (10ws) were tethered isometrically at optimal resting length, and responses were expressed as percent of the maximum to 63 mM potassium-chloride (%KCl). Cumulative concentration-response curves to KCl were equivalent for TSM from 2 and 10ws. However, maximal contraction to ACh in 2ws (168 +/- 8.4 %KCl) was greater than for 10ws (142 +/- 2.3 %KCl; P less than 0.02). Stimulus-response curves (field electrodes; AC source) demonstrated greater sensitivity for TSM in 10ws (stimulus causing 50% of the maximal response = 3.32 +/- 0.13 V in 2ws vs. 2.25 +/- 0.12 V in 10ws; P less than 0.001), indicating that the greater cholinomimetic responsiveness of 2ws did not result from augmented presynaptic nerve conduction. The AChase inhibitor, physostigmine, caused 1) greater sensitivity of responses elicited by electrical field stimulation in 2ws (P less than 0.05) but not in 10ws (P = NS), 2) augmentation of maximal responses to exogenous ACh in 10ws (27% increase; P less than 0.01) but not 2ws (2% increase; P = NS), and 3) a greater increase in sensitivity to cholinomimetic activation in 2ws compared with 10ws (P less than 0.02). These data demonstrate increased cholinergic contraction of TSM in 2 vs. 10ws that results at least in part from reduced AChase activity in the trachea of immature animals.