EXPRESSION OF AIRWAY CONTRACTILE PROPERTIES AND ACETYLCHOLINESTERASE ACTIVITY IN SWINE
EXPRESSION OF AIRWAY CONTRACTILE PROPERTIES AND ACETYLCHOLINESTERASE ACTIVITY IN SWINE
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DOI：
10.1152/jappl.1989.67.1.174
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发表时间：
1989-07-01
影响因子：
3.3
通讯作者：
LEFF, AR
中科院分区：
文献类型：
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作者：
MURPHY, TM;MITCHELL, RW;LEFF, AR
本实验采用离体和原位方法研究了成熟对17只2周龄（2周龄）和15只10周龄（10周龄）猪气管平滑肌收缩特性的影响。对副交感神经刺激的反应进行了研究，原位等距固定段。在较低频率下引起收缩[对电刺激的半最大响应（ES 50）= 6.7 . ±. 0.05 Hz]的频率（ES_（50）= 9.1 ± 0.1Hz）。0.4 Hz; P < 0.01）。尽管在2 ws中形态计量标准化横截面积存在显著差异（0.012 ± 0.0001），0.003cm 2）和10 ws（0.028 ±. 0.001 cm 2; P < 0.01），由副交感神经刺激引起的最大活动张力相似（12.4 ± 0.01 cm 2; P < 0.01）。3.2 g/cm，2 ws与13.3 ±。2.3 g/cm（10周）。在来自10头猪的25条气管平滑肌条的单独体外研究中，用钾取代的Krebs溶液（KCl）生成的浓度-反应曲线在2 ws和10 ws中相似。在另外58条（10头猪）肌条中，乙酰胆碱（ACh）刺激2 w时的最大主动力显著大于刺激10 w时的最大主动力（P < 0.001）。去除上皮细胞没有效果。10 ~（-7）M毒扁豆碱抑制胆碱酯酶后，10周时ACh刺激的反应增强（P < 0.02），而2 w时则无显著性差异。我们证明了在2 ws与10 ws中对迷走神经刺激的力产生和敏感性增加，这对应于体外对ACh的反应性增加。在2 ws的相对高反应性是特异性的胆碱能反应，并减弱至少部分由乙酰胆碱酯酶的活性成熟。
We studied the effect of maturation on contractile properties of tracheal smooth muscle from seventeen 2-wk-old swine (2ws) and fifteen 10-wk-old swine (10ws) in situ and in vitro. The response to parasympathetic stimulation was studied in situ in isometrically fixed segments. Contraction was elicited at lower frequencies [half-maximal response to electrical stimulation (ES50) = 6.7 .+-. 0.05 Hz] in 2ws than in 10ws (ES50 = 9.1 .+-. 0.4 Hz; P < 0.01). Despite substantial differences in morphometrically normalized cross-sectional area in 2ws (0.012 .+-. 0.003 cm2) and 10ws (0.028.+-. 0.001 cm2; P < 0.01), maximal active tension elicited by parasympathetic stimulation was similar (12.4 .+-. 3.2 g/cm in 2ws vs. 13.3 .+-. 2.3 g/cm in 10ws; P = NS). In separate in vitro studies in 25 tracheal smooth muscle strips from 10 swine, concentration-response curves generated with potassium-substituted Krebs solution (KCl) were similar in 2ws and 10ws. In 58 other strips (10 swine), maximal active force elicited with acetylcholine (ACh) in 2ws was significantly greater than for 10ws (P < 0.001). Removal of the epithelium had no effect. However, cholinesterase inhibition with 10-7 M physostigmine augmented the response to ACh in 10ws (P < 0.02) but not 2ws. We demonstrate increased force generation and sensitivity to vagal stimulation in 2ws vs. 10ws, which corresponds to increased reactivity to ACh in vitro. The relative hyperresponsiveness in 2ws is specific for cholinergic response and is attenuated at least in part by maturation of the activity of acetylcholinesterase enzyme.