Nerve Evoked Signaling in Urinary Bladder Smooth Muscle

膀胱平滑肌中的神经诱发信号

• 批准号: 7092012
• 负责人: MARK T NELSON
• 金额: $ 34.88万
• 依托单位: UNIVERSITY OF VERMONT & ST AGRIC COLLEGE
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-15 至 2008-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7092012
• 关键词: biological signal transduction; calcium channel; calcium flux; cholinergic receptors; confocal scanning microscopy; endoplasmic reticulum; gene expression; genetically modified animals; immunofluorescence technique; laboratory mouse; morphometry; muscarinic receptor; muscle contraction; neural transmission; protein kinase C; purinergic receptor; receptor coupling; smooth muscle; urinary bladder disorder; urinary bladder epithelium; urinary tract obstruction; voltage gated channel

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.

描述（由申请人提供）：膀胱平滑肌（UBSM）的核心功能是将神经输入转化为正常排尿反应，该功能随着出口阻塞而显着改变。 该提案重点关注这些通过胆碱能和嘌呤能途径的神经输入如何对 UBSM 中的钙 (Ca2+) 信号模式产生差异性影响，以及正常条件下和部分出口阻塞时的电和收缩反应。 尽管这些通路很重要，但我们对潜在的神经诱发兴奋收缩（E-C）耦合机制以及阻塞时发生的变化的了解仍然存在重大差距。 我们取得了重大进展，能够以高空间和时间分辨率测量完整的整个膀胱和膀胱条中的神经兴奋和局部 Ca2+ 信号。 我们在 UBSM 中发现了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，2）通过兰尼碱受体（RyR）从肌浆网（SR）局部释放钙。 目标 1 试图阐明 UBSM 将胆碱能和嘌呤能刺激解码为不同钙信号的新机制，这些信号不同地依赖于通过电压依赖性钙通道 (VDCC)、肌醇三磷酸受体 (IP3R) 和 SR 中的 RyR 进入的 Ca2+。 目标 2 重点关注 UBSM E-C 耦合机制，以响应胆碱能和嘌呤能机制引发的独特钙信号。 在目标 3 中，我们探讨了 VDCC 和 SR Ca2+ 负荷在介导正常和功能障碍膀胱中胆碱能和嘌呤能兴奋中的相互作用。 出口阻塞后 SR 功能障碍通过改变 UBSM 钙信号传导对胆碱能和嘌呤能刺激产生不同影响的假设将得到检验。 使用最先进的技术、基因改造的小鼠以及我们最近开发的部分膀胱出口梗阻的小鼠模型，拟议的研究将为正常膀胱和梗阻膀胱中胆碱能和嘌呤能途径对 UBSM 的差异影响提供新的见解。 这项研究的新发现将与理解 UBSM 中神经诱发 E-C 耦合的基本机制高度相关，并确定膀胱功能障碍的关键要素，因此与膀胱功能障碍的理解和治疗高度相关。