Mechanisms of airway hypercontractility in basenji-greyhound dogs.
Mechanisms of airway hypercontractility in basenji-greyhound dogs.
复制标题
巴森吉灵缇犬气道过度收缩的机制。
DOI：
10.1152/jappl.1987.63.5.2008
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发表时间：
1987
期刊：
影响因子：
--
通讯作者：
Leff,AR
中科院分区：
文献类型：
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作者：
Murphy,TM;Munoz,NM;Hirshman,CA;Blake,JS;Leff,AR
在五只巴森吉灵缇犬 (BG) 和六只杂种狗中，对收缩激动剂和气管和支气管平滑肌 (BSM) 反应的生理刺激的比较效果进行了等距原位研究。双侧迷走神经刺激（0-20 Hz、15-20 V、2 毫秒持续时间）产生的频率响应曲线引起杂种气管更大的最大收缩（36.8 +/- 8.1 对比 26.9 +/- 4.0 g/cm；P 小于 0.02），并在杂种 BSM 中表现出更大的响应性（对电刺激的半最大响应 3.0） +/- 1.1 vs. 7.0 +/- 0.5 Hz；P 小于 0.05) 与 BG 狗相比。然而，BG 犬对静脉注射乙酰甲胆碱 (MCh) 的毒蕈碱敏感性要高得多。平均剂量为 3.0 X 10(-10) mol/kg 的 BG 狗与 5.1 X 10(-9) mol/kg 的杂种对照犬相比，MCh 引起的收缩大于 1.5 g/cm（P 小于 0.03，Mann-Whitney 秩和检验）。与毒蕈碱反应相反，β-肾上腺素能阻断后静脉注射去甲肾上腺素引起的收缩反应在杂种狗和 BG 狗的气管和支气管中相似。我们的数据证实了先前在 BG 犬中气管反应低下的体外演示，并证明 BG 中由传出副交感神经刺激引起的收缩比杂种犬要少。然而，BG BSM 的突触后毒蕈碱反应性显着增加。我们得出的结论是，BG 狗气道反应性的一个组成部分直接取决于突触后产生的收缩力，这些收缩力是非几何依赖的、连接后的和激动剂特异性的。
The comparative effects of contractile agonists and physiological stimulation of the tracheal and bronchial smooth muscle (BSM) response were studied isometrically in situ in five Basenji-greyhound (BG) and six mongrel dogs. Frequency-response curves generated by bilateral stimulation of the vagus nerves (0–20 Hz, 15–20 V, 2-ms duration) elicited greater maximal contraction in mongrel trachea (36.8 +/- 8.1 vs. 26.9 +/- 4.0 g/cm; P less than 0.02) and exhibited greater responsiveness in mongrel BSM (half-maximal response to electrical stimulation 3.0 +/- 1.1 vs. 7.0 +/- 0.5 Hz; P less than 0.05) compared with BG dogs. However, muscarinic sensitivity to intravenous methacholine (MCh) was substantially greater in BG dogs; MCh caused contraction greater than 1.5 g/cm at a mean dose of 3.0 X 10(-10) mol/kg for BG dogs compared with 5.1 X 10(-9) mol/kg for mongrel controls (P less than 0.03, Mann-Whitney rank-sum test). In contrast to the muscarinic response, the contractile response elicited by intravenous norepinephrine after beta-adrenergic blockade was similar in trachea and bronchus for both mongrel and BG dogs. Our data confirm previous in vitro demonstration of tracheal hyporesponsiveness in BG dogs and demonstrate that the contraction resulting from efferent parasympathetic stimulation is less in the BG than mongrel dogs. However, postsynaptic muscarinic responsiveness of BG BSM is substantially increased. We conclude that a component of airway responsiveness in BG dogs depends directly on contractile forces generated postsynaptically that are nongeometry dependent, postjunctional, and agonist specific.