Pertussis toxin does not inhibit muscarinic-receptor-mediated phosphoinositide hydrolysis or calcium mobilization.
Pertussis toxin does not inhibit muscarinic-receptor-mediated phosphoinositide hydrolysis or calcium mobilization.
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百日咳毒素不抑制毒蕈碱受体介导的磷酸肌醇水解或钙动员。
DOI：
10.1042/bj2270933
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发表时间：
1985
期刊：
影响因子：
--
通讯作者：
Brown,JH
中科院分区：
文献类型：
--
作者：
Masters,SB;Martin,MW;Harden,TK;Brown,JH
百日咳毒素用于检查抑制性鸟嘌呤核苷酸调节蛋白 Ni 在毒蕈碱受体介导的磷酸肌醇周转和钙动员刺激中的作用。在培养的鸡心细胞中，百日咳毒素治疗抑制了毒蕈碱受体介导的异丙肾上腺素刺激的环 AMP 积累的减弱。这一发现与百日咳毒素阻断 Ni 将毒蕈碱受体与腺苷酸环化酶偶联的能力一致。相比之下，用百日咳毒素处理鸡心脏细胞或1321N1人星形细胞瘤细胞并不能阻断毒蕈碱受体介导的磷酸肌醇水解刺激，如在Li+存在下通过[3H]磷酸肌醇积累所测量的。通过将[3H]肌醇掺入磷脂酰肌醇来测量，百日咳毒素治疗对基础和毒蕈碱受体刺激的磷脂酰肌醇合成也几乎没有影响。毒蕈碱受体的激活也会增强 1321N1 细胞中 45Ca2+ 单向流出的速率；这种反应，就像磷酸肌醇水解一样，不能被百日咳毒素治疗所阻止。我们的数据表明，毒蕈碱受体不与磷酸肌醇水解或通过 Ni 的钙动员偶联。
Pertussis toxin was used to examine the role of the inhibitory guanine nucleotide regulatory protein, Ni, in muscarinic-receptor-mediated stimulation of phosphoinositide turnover and calcium mobilization. In cultured chick heart cells, pertussis-toxin treatment inhibited muscarinic-receptor-mediated attenuation of isoprenaline-stimulated cyclic AMP accumulation. This finding is consistent with the proposal that pertussis toxin blocks the capacity of Ni to couple muscarinic receptors to adenylate cyclase. In contrast, treatment of chick heart cells or 1321N1 human astrocytoma cells with pertussis toxin did not block muscarinic-receptor-mediated stimulation of phosphoinositide hydrolysis, as measured by [3H]inositol phosphate accumulation in the presence of Li+. Pertussis-toxin treatment also had little effect on basal and muscarinic-receptor-stimulated phosphatidylinositol synthesis, as measured by the incorporation of [3H]inositol into phosphatidylinositol. Activation of muscarinic receptors also enhances the rate of unidirectional 45Ca2+ efflux in 1321N1 cells; this response, like phosphoinositide hydrolysis, was not prevented by pertussis-toxin treatment. Our data suggest that muscarinic receptors are not coupled to phosphoinositide hydrolysis or calcium mobilization through Ni.