Inhibition of cholinergic neurotransmission in human airways by beta 2-adrenoceptors.
Inhibition of cholinergic neurotransmission in human airways by beta 2-adrenoceptors.
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β2-肾上腺素受体抑制人气道中的胆碱能神经传递。
DOI：
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发表时间：
1988
影响因子：
3.3
通讯作者：
P. Barnes
中科院分区：
文献类型：
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作者：
K. Rhoden;L. Meldrum;P. Barnes
本研究的目的是确定是否儿茶酚胺调节胆碱能神经传递在离体人气道平滑肌。支气管环悬挂在器官浴的张力等长测量，收缩引起的电场刺激（EFS）或外源性乙酰胆碱（ACh）。异丙肾上腺素，肾上腺素，去甲肾上腺素的效力顺序产生浓度依赖性抑制EFS和ACh的可比反应。然而，与对ACh的反应相比，观察到异丙肾上腺素对EFS反应的抑制效力差异为100倍（对EFS的IC 50 = 4.80 × 10（-8）M，对ACh的IC 50 = 3.70 × 10（-6）M），肾上腺素和去甲肾上腺素的抑制效力差异为10倍。异丙肾上腺素对EFS反应的抑制作用可被普萘洛尔和ICI 118551（β 2-拮抗剂）阻止，但不能被倍他洛尔（β 1-拮抗剂）阻止。酪胺对EFS引起的收缩没有影响。这些实验表明，β-受体激动剂抑制胆碱能神经诱导的收缩的人支气管更有力地比收缩引起的外源性乙酰胆碱，表明调制的胆碱能神经传递的连接前β 2受体。
The purpose of the study was to determine whether catecholamines modulate cholinergic neurotransmission in isolated human airway smooth muscle. Bronchial rings were suspended in organ baths for isometric measurement of tension, and contractions were induced by either electrical field stimulation (EFS) or exogenous acetylcholine (ACh). Isoproterenol, epinephrine, and norepinephrine in that order of potency produced concentration-dependent inhibition of comparable responses to EFS and ACh. However a potency difference of 100-fold for isoproterenol (IC50 = 4.80 X 10(-8) M for EFS and 3.70 X 10(-6) M for ACh) and 10-fold for both epinephrine and norepinephrine was observed for inhibition of responses to EFS compared with responses to ACh. The inhibitory effects of isoproterenol on responses to EFS were prevented by propranolol and ICI 118551 (a beta 2-antagonist) but not by betaxolol (a beta 1-antagonist). Tyramine had no effect on contractions elicited by EFS. These experiments demonstrate that beta-agonists inhibit cholinergic nerve-induced contractions of human bronchi more potently than contractions induced by exogenous ACh, suggesting modulation of cholinergic neurotransmission by prejunctional beta 2-receptors.