Adenosine receptor-mediated calcium mobilization in cortical collecting tubule cells.
Adenosine receptor-mediated calcium mobilization in cortical collecting tubule cells.
复制标题
皮质集合管细胞中腺苷受体介导的钙动员。
DOI：
10.1152/ajpcell.1988.255.5.c581
复制
发表时间：
1988
期刊：
影响因子：
--
通讯作者：
Spielman,WS
中科院分区：
文献类型：
--
作者：
Arend,LJ;Burnatowska-Hledin,MA;Spielman,WS
为了探讨腺苷上皮细胞作用的细胞机制，我们研究了培养的兔皮质集合管(RCCT)细胞中腺苷受体-效应器的偶联。我们先前报道，在免疫解剖分离的RCCT细胞中，有效的A2腺苷类似物[5‘-N-乙基碳酰胺腺苷(NECA)]刺激cAMP的产生[有效浓度50%(EC50)=1微米]，而有效A1类似物[N6-环己基腺苷(CHA)和R-N6-苯基异丙基腺苷(PIA)]抑制基础和AVP刺激的cAMP产生(EC50=5 nM)。目前的研究是为了确定RCCT细胞中的腺苷受体是否也连接到导致细胞内游离钙动员的信号转导系统。用荧光钙指示剂Fura-2负载RCCT细胞，并用腺苷类似物NECA、CHA和PIA处理。三种腺苷类似物均可产生剂量依赖性(1 nM-0.1 mM)的瞬时细胞内钙离子浓度升高，且作用强度相同(EC50=0.5微米)。用乙二醇双(β-氨基乙基醚)N，N，N‘，N’四乙酸(EGTA)螯合细胞外钙并不能消除细胞内钙的增加。腺苷受体拮抗剂1，3-二乙基-8-丙基黄嘌呤和8-环戊基-1，3-二丙基黄嘌呤，以及用百日咳毒素预处理RCCT细胞，均可阻断细胞内钙离子的增加。这些结果表明，RCCT细胞除了与cAMP的刺激和抑制有关的腺苷受体外，还有一个百日咳毒素敏感的受体系统，导致细胞内钙的动员。
To investigate the cellular mechanisms underlying the epithelial actions of adenosine, we studied adenosine receptor-effector coupling in cultured rabbit cortical collecting tubule (RCCT) cells. We previously reported, in RCCT cells isolated by immunodissection, that a potent A2 adenosine analogue [5'-N-ethylcarboxamideadenosine (NECA)] stimulates cAMP production [effective concentration 50% (EC50) = 1 microM], and potent A1 analogues [N6-cyclohexyladenosine (CHA) and R-N6-phenylisopropyladenosine (PIA)] inhibit basal and AVP-stimulated cAMP production (EC50 = 5 nM). The present study was undertaken to determine whether adenosine receptors in RCCT cells are also coupled to a signal transduction system leading to the mobilization of intracellular free calcium. RCCT cells were loaded with the fluorescent calcium indicator, fura-2, and were treated with the adenosine analogues NECA, CHA, and PIA. All three adenosine analogues produced dose-dependent (1 nM-0.1 mM), transient increases in intracellular calcium concentration with equal potency (EC50 = 0.5 microM). Chelation of extracellular calcium with ethyleneglycol-bis(beta-aminoethyl ether)N,N,N',N' tetraacetic acid (EGTA) did not abolish the increase in calcium. The adenosine receptor antagonists, 1,3-diethyl-8-propylxanthine and 8-cyclopentyl-1,3-dipropylxanthine, and pretreatment of RCCT cells with pertussis toxin blocked the increase in calcium. These results demonstrate that RCCT cells have, in addition to adenosine receptors associated with the stimulation and inhibition of cAMP, a pertussis-toxin sensitive receptor system that leads to the mobilization of intracellular calcium.