Amiloride-sensitive ion channels in urinary bladder epithelium involved in mechanosensory transduction by modulating stretch-evoked adenosine triphosphate release
Amiloride-sensitive ion channels in urinary bladder epithelium involved in mechanosensory transduction by modulating stretch-evoked adenosine triphosphate release
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DOI：
10.1016/j.urology.2007.01.039
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发表时间：
2007-03-01
期刊：
影响因子：
2.1
通讯作者：
Takeda, Masayuki
中科院分区：
文献类型：
--
作者：
Du, Shuqi;Araki, Isao;Takeda, Masayuki
目的探讨机械敏感离子通道（包括上皮Na+通道（ENaC））参与大鼠膀胱机械感觉传导的可能性。方法采用连续输注膀胱术，观察经静脉灌注阿米洛利（ENaC阻滞剂）对聚氨酯麻醉雌性大鼠排尿反射的影响。有或没有上皮的膀胱条悬浮在器官浴中，受到不同程度的机械拉伸（高达50%）。采用荧光素-荧光素酶法定量测定阿米洛利拉伸诱导三磷酸腺苷（ATP）释放的变化。采用逆转录-聚合酶链反应检测ENaC基因表达。免疫荧光染色检测ENaC蛋白的表达和定位。结果膀胱灌注1 mM阿米洛利可显著降低膀胱充注时反射性排尿的频率。阿米洛利的这种作用通过冲洗药物是可逆的。尿压峰值振幅不受阿米洛利的影响。拉伸引起的ATP释放，其中大部分（超过90%）来自上皮层，被1 mM阿米洛利大大减少（从443到22%的基础水平，拉伸原始长度的50%）。α、β和γ - enac亚基蛋白和基因在大鼠膀胱上皮中表达。结论大鼠膀胱上皮中表达的包括ENaC在内的阿米洛利敏感的机械敏感通道可能通过控制拉伸引起的ATP释放参与机械感觉转导机制。(c) 2007爱思唯尔公司
OBJECTIVES To examine the possibility that mechanosensitive ion channels, including epithelial Na+ channels (ENaC), are implicated in mechanosensory transduction of the rat urinary bladder.METHODS Cystometry with continuous infusion was performed to investigate the effect of intravesically perfused amiloride (a blocker of ENaC) on micturition reflex in urethane-anesthetized female rats. Bladder strips with or without epithelium suspended in organ bath were subjected to varying degrees of mechanical stretch (up to 50%). A luciferin-luciferase assay was used to quantify the change of stretch-evoked adenosine triphosphate (ATP) release by amiloride. The ENaC gene expression was assessed by reverse transcriptase-polymerase chain reaction. The expression and localization of ENaC proteins was examined using immunofluorescent staining.RESULTS The intravesical perfusion of 1 mM amiloride significantly reduced the frequency of reflex voiding during bladder filling. This effect of amiloride was reversible by washing out the drug. The peak amplitude of micturition pressure was not affected by amiloride. The stretch-evoked ATP release, most of which (more than 90%) came from epithelial layer, was greatly diminished by 1 mM amiloride (from 443 to a 22% increase from basal level at 50% stretch of the original length). The alpha, beta, and gamma-ENaC subunit proteins and genes were expressed in the rat bladder epithelium.CONCLUSIONS The amiloride-sensitive mechanosensitive channel, including ENaC, expressed in the rat bladder epithelium might be involved in the mechanosensory transduction mechanism by controlling stretch-evoked ATP release. (c) 2007 Elsevier Inc.