Seifert R, Hagelüken A, Höer A, Höer D, Grünbaum L, Offermanns S, Schwaner I, Zingel V, Schunack W, Schultz G
Institut für Pharmakologie, Freie Universität Berlin, Germany.
Mol Pharmacol. 1994 Apr;45(4):578-86.
In dibutyryl-cAMP-differentiated HL-60 cells, histamine H1 and formyl peptide receptors mediate increases in the cytosolic Ca2+ concentration ([Ca2+]i) via pertussis toxin-sensitive G proteins of the Gi family. We compared the effects of 2-(3-chlorophenyl)-histamine (CPH) [2-[2-(3-chlorophenyl)-1H-imidazol-4-yl] ethanamine], one of the most potent and selective H1 receptor agonists presently available, with those of histamine and N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP) in these cells. CPH increased [Ca2+]i through Ca2+ mobilization and Ca2+ influx. Unlike histamine-induced rises in [Ca2+]i, those induced by CPH were not desensitized in a homologous manner, and there was no cross-desensitization between CPH and histamine. Like fMLP, CPH activated phospholipases C and D, tyrosine phosphorylation, superoxide anion formation, and azurophilic granule release. The effects of CPH on [Ca2+]i, phospholipase D, and superoxide anion formation were inhibited by pertussis toxin. CPH and fMLP stimulated high affinity GTP hydrolysis by Gi proteins in HL-60 membranes. They also enhanced binding of guanosine-5'-O-(3-thio)triphosphate and GTP azidoanilide to, and cholera toxin-catalyzed ADP-ribosylation of, Gi protein alpha subunits. Histamine receptor antagonists did not inhibit the stimulatory effects of CPH, and CPH did not reduce fMLP binding in HL-60 membranes. Our data suggest that CPH activates Gi proteins in HL-60 cells through a receptor agonist-like mechanism that is, however, independent of known histamine receptor subtypes and formyl peptide receptors. CPH may be an agonist at an as yet unknown histamine receptor subtype or, by analogy with other cationic-amphiphilic substances, may activate G proteins directly. Future studies will have to take into consideration the fact that CPH, in addition to activating H1 receptors, may show other, most unexpected, stimulatory effects on G protein-mediated signal transduction processes.
在二丁酰环磷腺苷（dibutyryl-cAMP）分化的HL-60细胞中，组胺H1受体和甲酰肽受体通过Gi家族中对百日咳毒素敏感的G蛋白介导细胞溶质Ca2+浓度（[Ca2+]i）升高。我们比较了目前可用的最有效且最具选择性的H1受体激动剂之一2-(3-氯苯基)-组胺（CPH）[2-[2-(3-氯苯基)-1H-咪唑-4-基]乙胺]与组胺和N-甲酰-L-蛋氨酰-L-亮氨酰-L-苯丙氨酸（fMLP）对这些细胞的作用。CPH通过Ca2+动员和Ca2+内流增加[Ca2+]i。与组胺诱导的[Ca2+]i升高不同，CPH诱导的[Ca2+]i升高不会以同源方式脱敏，并且CPH与组胺之间不存在交叉脱敏。与fMLP一样，CPH激活磷脂酶C和D、酪氨酸磷酸化、超氧阴离子形成以及嗜天青颗粒释放。CPH对[Ca2+]i、磷脂酶D和超氧阴离子形成的作用被百日咳毒素抑制。CPH和fMLP刺激HL-60细胞膜中Gi蛋白的高亲和力GTP水解。它们还增强了鸟苷-5'-O-(3-硫代)三磷酸（guanosine-5'-O-(3-thio)triphosphate）和GTP叠氮苯胺（GTP azidoanilide）与Gi蛋白α亚基的结合，以及霍乱毒素催化的Gi蛋白α亚基的ADP核糖基化。组胺受体拮抗剂不抑制CPH的刺激作用，并且CPH不降低HL-60细胞膜中fMLP的结合。我们的数据表明，CPH通过一种类似受体激动剂的机制激活HL-60细胞中的Gi蛋白，然而，该机制独立于已知的组胺受体亚型和甲酰肽受体。CPH可能是一种尚未知晓的组胺受体亚型的激动剂，或者类似于其他阳离子两亲性物质，可能直接激活G蛋白。未来的研究将不得不考虑到这样一个事实，即CPH除了激活H1受体外，可能对G蛋白介导的信号转导过程表现出其他最意想不到的刺激作用。
