Purinergic regulation of guinea pig suburothelial myofibroblasts
Purinergic regulation of guinea pig suburothelial myofibroblasts
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DOI：
10.1113/jphysiol.2004.067934
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发表时间：
2004-08-15
影响因子：
5.5
通讯作者：
Fry, CH
中科院分区：
文献类型：
--
作者：
Wu, C;Sui, GP;Fry, CH
的Ca 2+调节和电生理特性的豚鼠上皮下肌成纤维细胞已被测量，以探讨其潜在的作用，在膀胱充盈的感觉，由于其战略地位之间的尿路刺激和传入纤维。先前的工作已经表明膀胱壁的伸展释放ATP分离出波形蛋白染色阳性的细胞。约45%的细胞（中位膜电容13.3 pF）表现出自发去极化至约-25 mV，具有生理Cl-梯度（频率2.6 +/- 1.5 min（-1），持续时间14.5 +/- 2.2 s，n = 15）。在电压钳下记录自发内向电流（频率1.5 +/- 0.2 min（-1），持续时间14.5 +/- 7.0 s，n = 18），具有相似的逆转电位。自发电流之前的细胞内Ca 2+瞬变的幅度是独立的膜电位。所有测试的细胞通过产生细胞内Ca 2+瞬变，然后通过内向电流响应ATP;电流具有与其自发对应物相似的逆转电位和斜率电导。ATP产生的瞬变被UTP和ADP模拟，但不被α，β-亚甲基-ATP（1-10 μ M）或CTP（30 μ M）模拟，表明ATP通过P2 Y受体起作用。瞬变部分衰减1毫米苏拉明，但PPADS（80 μ M）没有效果。这些数据表明，ATP通过P2 Y受体起作用，但对P2 Y（1）拮抗剂MRS 2179有抗性。用肝素和TMB-8进行细胞内灌注可消除ATP产生的瞬变，表明IP 3是细胞内第二信使。细胞外[Cl-]减少12倍，自发和ATP产生的电流的逆转电位移动约+45 mV，1 mm DIDS大大衰减电流。暴露于毒蕈碱激动剂卡巴胆碱时未产生瞬变。我们认为这些细胞可能通过对ATP的反应在膀胱充盈的感觉中起调节作用。下一步将阐明它们将尿路上皮ATP释放与传入兴奋偶联的确切机制。
The Ca2+-regulating and electrophysiological properties of guinea-pig suburothelial myofibroblasts have been measured in order to investigate their potential role in the sensation of bladder fullness, due to their strategic position between the urothelium and afferent fibres. Previous work has shown that stretch of the bladder wall releases ATP Cells that stain positively for vimentin were isolated. About 45% of cells (median membrane capacitance 13.3 pF) exhibited spontaneous depolarizations to about -25 mV with a physiological Cl- gradient (frequency 2.6 +/- 1.5 min(-1), duration 14.5 +/- 2.2 s, n = 15). Under voltage-clamp spontaneous inward currents (frequency 1.5 +/- 0.2 min(-1), duration 14.5 +/- 7.0 s, n = 18) were recorded, with a similar reversal potential. The spontaneous currents were preceded by intracellular Ca2+ transients with a magnitude that was independent of membrane potential. All cells tested responded to ATP by generating an intracellular Ca2+ transient, followed by inward currents; the currents had a similar reversal potential and slope conductance to their spontaneous counterparts. ATP-generated transients were mimicked by UTP and ADP but not by alpha,beta-methylene-ATP (1-10 muM) or CTP (30 muM), indicating that ATP acts via a P2Y receptor. Transients were partially attenuated by 1 mm suramin but PPADS (80 muM) had no effect. These data indicate that ATP acts via a P2Y receptor, but responses were resistant to the P2Y(1) antagonist MRS2179. ATP-generated transients were abolished by intracellular perfusion with heparin and TMB-8 indicating that IP3 was the intracellular second messenger. The reversal potentials of the spontaneous and ATP-generated currents were shifted by about +45 mV by a 12-fold reduction of the extracellular [Cl-] and the currents were greatly attenuated by 1 mm DIDS. No transients were generated on exposure to the muscarinic agonist carbachol. We propose that these cells may play a regulatory step in the sensation of bladder fullness by responding to ATP The precise mechanism whereby they couple urothelial ATP release to afferent excitation is the next step to be elucidated.