ATP induces contraction mediated by the P2Y2 receptor in rat intestinal subepithelial myofibroblasts
ATP induces contraction mediated by the P2Y2 receptor in rat intestinal subepithelial myofibroblasts
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DOI：
10.1016/j.ejphar.2011.01.047
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发表时间：
2011-04-25
影响因子：
5
通讯作者：
Ozaki, Hiroshi
中科院分区：
文献类型：
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作者：
Nakamura, Tatsuro;Iwanaga, Koichi;Ozaki, Hiroshi
肠上皮下肌成纤维细胞（IMF）存在于上皮细胞膜下，直接面对分布在固有层中的粘膜微血管毛细血管表面。在胃肠道中，ATP响应于机械刺激从上皮细胞和内皮细胞释放。虽然已经报道了机械刺激引起同步的Ca 2+波在培养的IMF，ATP刺激的收缩反应还没有被检查。本研究的目的是阐明肌内脂肪细胞对ATP反应性收缩的机制。ATP（1-30 μ M）以浓度依赖性方式诱导收缩。这些收缩被LaCl 3（100-300 μ M）和无Ca 2+溶液（0.5 mM EGTA）抑制。Fura-2/Ca ~（2+）信号表明ATP（1-10 μ M）引起细胞内Ca ~（2+）浓度（[Ca ~（2+）]（i））的瞬时增加。此外，α-β-亚甲基-ATP（10、30和300 μ M），一种浓度高于100 μ M的广谱P2 X激动剂，既不诱导收缩，也不诱导[Ca 2 +]（i）升高。UTP（1-30 μ M）是啮齿类动物中的一种选择性P2 Y（2）和P2 Y（4）激动剂，诱导浓度依赖性收缩和[Ca 2 +]（i）增加，而ADP和UDP（10 μ M）不诱导收缩。用相对选择性的P2 Y（2）拮抗剂苏拉明（30-100 μ M）预处理，强烈抑制ATP和UTP诱导的收缩和[Ca ~（2+）]（i）的增加。然而，磷酸吡哆醛-6-偶氮苯基-2 ′，4 ′-二磺酸盐（PPADS：10-30 μ M），一种几种P2 X和P2 Y的受体拮抗剂，但对P2 Y（2）受体的作用较弱，不能抑制ATP和UTP诱导的收缩和[Ca ~（2+）]（i）的增加。RT-PCR检测到P2 Y（1）和P2 Y（2）受体mRNA在IMF中的表达，但未检测到P2 Y（4）和P2 Y（6）受体mRNA的表达。这些结果表明，ATP诱导IMF的[Ca 2 +]（i）依赖性收缩，这是通过P2 Y（2）受体介导的。(C)2011 Elsevier B. V.保留所有权利。
Intestinal subepithelial myofibroblasts (IMFs) exist just under the epithelial membrane directly facing the mucosal microvascular capillary surface distributed in the lamina propria. In the gastrointestinal tract, ATP is released from epithelial and endothelial cells in response to mechanical stimuli. Although it has been reported that mechanical stimuli evoke synchronized Ca2+ waves in cultured IMFs, the contractile responses by ATP stimulation have not been examined. The aim of this study was to clarify the mechanism of the contraction of IMFs in response to ATP. ATP (1-30 mu M) induced contraction in a concentration-dependent manner. These contractions were inhibited by LaCl3 (100-300 mu M) and by Ca2+-free solution (0.5 mM EGTA). Fura-2/Ca2+ signals indicated that ATP (1-10 mu M) elicited transient increases in intracellular Ca2+ concentration ([Ca2+](i)). In addition, alpha beta-methylene-ATP (10, 30 and 300 mu M), a broad spectrum P2X agonist at a concentration higher than 100 mu M, induced neither contraction nor [Ca2+](i) rise. UTP (1-30 mu M), a selective P2Y(2) and P2Y(4) agonist in rodent, induced concentration-dependent contractions and [Ca2+](i) increases, whereas ADP and UDP (10 mu M) did not induce contractions. Pretreatment with suramin (30-100 mu M), a relatively selective P2Y(2) antagonist, strongly inhibited ATP- and UTP-induced contractions and [Ca2+](i) increases. However, pyridoxal-phosphate-6-azophenyl-2',4'-disulfonate (PPADS: 10-30 mu M), a receptor antagonist for several P2X and P2Y but less effective to P2Y(2) receptor, failed to inhibit ATP- and UTP-induced contractions and [Ca2+](i) increases. By RT-PCR, mRNA expressions of the P2Y(1) and P2Y(2) receptors, but not P2Y(4) or P2Y(6), were detected in IMFs. These results suggest that ATP induces [Ca2+](i)-dependent contraction in IMFs, which is mediated through the P2Y(2) receptor. (C) 2011 Elsevier B.V. All rights reserved.