The muscarinic receptors of airway smooth muscle: their characterization in vitro.
The muscarinic receptors of airway smooth muscle: their characterization in vitro.
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气道平滑肌的毒蕈碱受体：其体外表征。
DOI：
10.1152/jappl.1982.52.4.1084
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发表时间：
1982
期刊：
影响因子：
--
通讯作者：
Roberts,JM
中科院分区：
文献类型：
--
作者：
Murlas,C;Nadel,JA;Roberts,JM
我们使用放射性配基结合和体外肌肉收缩技术来表征犬气管平滑肌的M胆碱能受体。氚毒碱拮抗剂苯甲酸奎宁酯([~3H]QNB)与气管平滑肌微粒制剂无结合，具有高亲和力、饱和性、药理专一性和立体选择性。结合反应的平衡解离常数为33+/-3 pM(平均值+/-SE)。结合部位的浓度为410+/-34pmol/g蛋白。毒扁豆碱类药物抑制[~3H]QNB结合的能力与它们在体外对气管平滑肌收缩的相对作用平行。我们发现麻醉剂利多卡因和丁卡因以及尼古丁能拮抗剂D-管库拉林是[~3H]QNB与气管平滑肌结合的竞争性抑制剂。组胺、氨茶碱和肾上腺素能激动剂不起竞争性抑制作用。鸟嘌呤核苷酸5‘-亚胺基二磷酸降低了M受体激动剂乙酰胆碱与高亲和力结合位点(S)竞争的能力，但对M受体拮抗剂阿托品的结合影响很小。所描述的放射性配基结合和体外收缩技术正被用于研究疾病或治疗过程中呼吸道平滑肌M受体的可能变化。
We have used radioligand binding and in vitro muscle contraction techniques to characterize the muscarinic cholinergic receptors of canine tracheal smooth muscle. The tritiated muscarinic antagonist, quinuclidinyl benzilate ([3H]QNB), bound no particulate preparations of tracheal smooth muscle with high affinity, saturability, pharmacologic specificity, and stereoselectivity. The equilibrium dissociation constant for the binding reaction was 33 +/- 3 pM (mean +/- SE). The concentration of binding sites was 410 +/- 34 pmol/g protein. The ability of muscarinic agents to inhibit [3H]QNB binding paralleled their relative effects on tracheal smooth muscle contraction in vitro. We found the anesthetic agents, lidocaine and tetracaine, and the nicotonic cholinergic antagonist d-tubocurarine, were competitive inhibitors of [3H]QNB binding to the tracheal smooth muscle preparations. Histamine, aminophylline, and adrenergic agonists did not act as competitive inhibitors. The guanine nucleotide, guanyl-5′-imidodiphosphate, reduced the ability of the muscarinic agonist, acetylcholine, to compete with high affinity for [3H]QNB binding site(s) in tracheal smooth muscle but had minimal effects on the binding of the muscarinic antagonist, atropine. THe radioligand binding and in vitro contraction techniques described are being used to study the possible alteration of muscarinic receptors of airway smooth muscle in disease or from treatment.