Ca2+ signalling in mouse urethral smooth muscle in situ: role of Ca2+ stores and Ca2+ influx mechanisms
Ca2+ signalling in mouse urethral smooth muscle in situ: role of Ca2+ stores and Ca2+ influx mechanisms
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DOI：
10.1113/jp275719
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发表时间：
2018-04-15
影响因子：
5.5
通讯作者：
Sanders, Kenton M.
中科院分区：
文献类型：
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作者：
Drumm, Bernard T.;Rembetski, Benjamin E.;Sanders, Kenton M.
尿道平滑肌细胞（USMCs）产生肌张力，有助于尿失禁。目前，对USMCs中的Ca2+信号传导知之甚少，因此对兴奋-收缩耦合所需的Ca2+来源知之甚少。我们使用基因编码的Ca2+传感器GCaMP3在USMCs中选择性表达，表征了完整尿道肌肉中USMCs中的Ca2+信号。USMCs发射自发的细胞内Ca2+波，不通过肌肉束在细胞间传播。Ca2+波对1肾上腺素受体激动剂苯肾上腺素（10m）和ATP （10m）的响应显著增加。Ca2+波被一氧化氮供体DEA NONOate （10m）抑制。Ca2+内流和释放从肌浆网储存有助于Ca2+波，因为Ca2+游离洗浴液和阻断肌浆Ca2+- atp酶废除活性。细胞内Ca2+释放涉及到ryanodine受体和肌醇三磷酸受体之间的合作，因为丁卡因和ryanodine （100m）以及xestospongin C （1m）减少了Ca2+波。Ca2+波对l型Ca2+通道调节剂硝苯地平（1m）、尼卡地平（1m）、伊地平（1m）和FPL 64176 （1m）不敏感，对t型Ca2+通道拮抗剂NNC-550396 （1m）和ta - a2 （1m）不影响。Ca2+波被储存Ca2+进入阻滞剂SKF 96365 （10m）和Orai拮抗剂GSK-7975A （1m）减少。后者还减少了苯肾上腺素引起的尿道收缩，表明Orai可以作为受体操作的通道有效地起作用。总之，小鼠USMCs中的Ca2+波是尿道肌肉兴奋-收缩偶联Ca2+的来源。
Urethral smooth muscle cells (USMCs) generate myogenic tone and contribute to urinary continence. Currently, little is known about Ca2+ signalling in USMCs in situ, and therefore little is known about the source(s) of Ca2+ required for excitation-contraction coupling. We characterized Ca2+ signalling in USMCs within intact urethral muscles using a genetically encoded Ca2+ sensor, GCaMP3, expressed selectively in USMCs. USMCs fired spontaneous intracellular Ca2+ waves that did not propagate cell-to-cell across muscle bundles. Ca2+ waves increased dramatically in response to the 1 adrenoceptor agonist phenylephrine (10m) and to ATP (10m). Ca2+ waves were inhibited by the nitric oxide donor DEA NONOate (10m). Ca2+ influx and release from sarcoplasmic reticulum stores contributed to Ca2+ waves, as Ca2+ free bathing solution and blocking the sarcoplasmic Ca2+-ATPase abolished activity. Intracellular Ca2+ release involved cooperation between ryanadine receptors and inositol trisphosphate receptors, as tetracaine and ryanodine (100m) and xestospongin C (1m) reduced Ca2+ waves. Ca2+ waves were insensitive to L-type Ca2+ channel modulators nifedipine (1m), nicardipine (1m), isradipine (1m) and FPL 64176 (1m), and were unaffected by the T-type Ca2+ channel antagonists NNC-550396 (1m) and TTA-A2 (1m). Ca2+ waves were reduced by the store operated Ca2+ entry blocker SKF 96365 (10m) and by an Orai antagonist, GSK-7975A (1m). The latter also reduced urethral contractions induced by phenylephrine, suggesting that Orai can function effectively as a receptor-operated channel. In conclusion, Ca2+ waves in mouse USMCs are a source of Ca2+ for excitation-contraction coupling in urethral muscles.