Muscarinic receptor subtypes on rat pancreatic acini: secretion and binding studies.
Muscarinic receptor subtypes on rat pancreatic acini: secretion and binding studies.
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大鼠胰腺腺泡上的毒蕈碱受体亚型：分泌和结合研究。
DOI：
10.1152/ajpgi.1986.251.2.g275
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发表时间：
1986
期刊：
影响因子：
--
通讯作者：
Owyang,C
中科院分区：
文献类型：
--
作者：
Louie,DS;Owyang,C
用特异性毒蕈碱受体拮抗剂研究大鼠胰腺腺泡细胞上毒蕈碱受体亚型的特征，以研究淀粉酶分泌和[3 H]东莨菪碱（[3 H]NMS）的结合。将大鼠胰腺腺泡分散在HEPES-Ringer缓冲液中，并与乙酰胆碱+/- 4-二苯基乙酰氧基-N-甲基哌啶-碘甲烷（4-DAMP，一种特异性M2毒蕈碱受体拮抗剂）或+/-哌仑西平（一种特异性M1毒蕈碱受体拮抗剂）孵育。4-DAMP（10（-9）至10（-6）M）引起乙酰胆碱剂量-反应曲线进行性平行位移，而最大淀粉酶释放无变化。只有高浓度的哌仑西平（10（-6）至10（-4）M）引起乙酰胆碱的剂量-反应曲线的急剧移动。Schild数据分析表明，4-DAMP的抑制常数（Ki）为200 pM，哌仑西平为183 nM。Schild回归线的斜率与1没有不同，表明竞争性抑制。50 pM [3 H]NMS的结合具有特异性、快速性和可饱和性。[3 H]NMS结合被增加浓度的4-DAMP或哌仑西平取代，表观Ki分别为102 pM和330 nM，并且相似的最大结合水平为60 fmol/mg prot。我们已经证明，4-DAMP抑制淀粉酶释放和结合的效力比哌仑西平高约1,000倍，表明胆碱能刺激的淀粉酶从胰腺腺泡释放是由M2毒蕈碱受体介导的。
Characterization of muscarinic receptor subtypes on rat pancreatic acinar cells was examined by using specific muscarinic receptor antagonists to study amylase secretion and binding of [N-methyl-3H]scopolamine ([3H]NMS). Rat pancreatic acini were dispersed in HEPES-Ringer buffer and incubated with acetylcholine +/- 4-diphenylacetoxy-N-methylpiperadine-methiodide (4-DAMP, a specific M2 muscarinic receptor antagonist) or +/- pirenzepine (a specific M1 muscarinic receptor antagonist). 4-DAMP (10(-9) to 10(-6) M) caused a progressive parallel rightward shift in the acetylcholine dose-response curve without a change in maximal amylase release. Only high concentrations of pirenzepine (10(-6) to 10(-4) M) caused a rightward shift in the dose-response curve to acetylcholine. Schild analysis of the data indicated an inhibitory constant (Ki) of 200 pM for 4-DAMP and 183 nM for pirenzepine. The slope of the Schild regression lines was not different from unity, suggesting competitive inhibition. Binding of 50 pM [3H]NMS was specific, rapid, and saturable. [3H]NMS binding was displaced by increasing concentrations of 4-DAMP or pirenzepine with apparent Ki's of 102 pM and 330 nM, respectively, and similar maximal binding levels of 60 fmol/mg prot. We have demonstrated that 4-DAMP has an approximately 1,000-fold greater potency than pirenzepine to inhibit amylase release and binding, indicating that cholinergic-stimulated amylase release from pancreatic acini is mediated by M2 muscarinic receptors.