Nerve Evoked Signaling in Urinary Bladder Smooth Muscle

描述（由申请人提供）：膀胱平滑肌（UBSM）的中枢功能是将神经输入转化为正常排尿反应，该功能在出口梗阻时发生显著改变。 这项建议的重点是如何通过胆碱能和嘌呤能通路的神经输入差异影响钙（Ca 2+）信号模式在UBSM，在正常条件下，并与部分出口梗阻的电和收缩反应。 尽管这些途径的重要性，主要差距仍然在我们的知识o 1潜在的神经诱发的兴奋-收缩（E-C）耦合机制和发生的变化与阻塞。 在一个重大的进步，我们已经能够测量，具有高的空间和时间分辨率，神经兴奋，和当地的Ca 2+信号在完整的整个膀胱和膀胱条。 我们已经确定了UBSM中两种不同的局部钙瞬变：1）神经诱发的钙瞬变，通过嘌呤能受体介导，和2）钙从肌浆网（SR）通过兰尼碱受体（RyRs）的局部释放。 目的1阐明UBSM将胆碱能和嘌呤能刺激解码为不同的钙信号的新机制，这些钙信号分别依赖于电压依赖性钙通道（VDCC）、三磷酸肌醇受体（IP 3Rs）和RyRs。目的2研究UBSM对胆碱能和嘌呤能钙信号的E-C偶联机制。 在目的3中，我们探讨VDCC和SR Ca 2+负荷在介导正常和功能障碍膀胱的胆碱能和嘌呤能兴奋中的相互作用。 将检验出口梗阻后SR功能障碍通过改变UBSM钙信号传导而不同地影响胆碱能和嘌呤能刺激的假设。 使用最先进的技术，基因改变的小鼠，和我们最近开发的部分膀胱出口梗阻的小鼠模型，拟议的研究将提供新的见解胆碱能和嘌呤能通路对UBSM在正常和梗阻膀胱的差异影响。 这项研究的新发现将与理解UBSM中神经诱发的E-C偶联的基本机制高度相关，并确定膀胱功能障碍的关键因素，因此应该与膀胱功能障碍的理解和治疗高度相关。

DESCRIPTION (provided by applicant): A central function of urinary bladder smooth muscle (UBSM) is the translation of neural inputs into a normal micturition response, a function that is dramatically altered with outlet obstruction. This proposal focuses on how these neural inputs through cholinergic and purinergic pathways differentially impact calcium (Ca2+) signal patterning in UBSM, and on electrical and contractile responses under normal conditions and with partial outlet obstruction. Despite the importance of these pathways, major gaps remain in our knowledge o1 the underlying nerve-evoked excitation-contraction (E-C) coupling mechanisms and the changes that occur with obstruction. In a major advance, we have been able to measure, with high spatial and temporal resolution, nerve excitation, and local Ca2+ signals in intact whole urinary bladders and bladder strips. We have identified two distinct local calcium transients in UBSM: 1) nerve-evoked calcium transients, mediated through purinergic receptors, and 2) the local release of calcium from the sarcoplasmic reticulum (SR) through ryanodine receptors (RyRs). Aim 1 seeks to elucidate the novel mechanisms by which UBSM decodes cholinergic and purinergic stimulation into different calcium signals, which differentially depend on Ca2+ entry through voltage-dependent calcium channels (VDCC), inositol triphosphate receptors (IP3Rs) and RyRs in the SR. Aim 2 focuses on UBSM E-C coupling mechanisms in response to the unique calcium signals elicited by cholinergic and purinergic mechanisms. In Aim 3, we explore the interaction of VDCC and SR Ca2+ load in mediating cholinergic and purinergic excitation in normal and dysfunctional bladders. The hypothesis that SR dysfunction following outlet obstruction differentially affects cholinergic and purinergic stimulation by altered UBSM calcium signaling will be tested. Using state-of-the-art techniques, genetically altered mice, and our recently developed mouse model of partial bladder outlet obstruction, the proposed study will provide new insights into the differential impact of cholinergic and purinergic pathways on UBSM in normal and obstructed bladders. The novel findings of this study will be highly relevant to understanding fundamental mechanisms of nerve-evoked E-C coupling in UBSM, and identify key elements that underlie bladder dysfunction, and as such should be highly relevant to the understanding and treatment of bladder dysfunction.