Cellular electrophsyiology of vasculatures in the inner ear

摘要 血液循环障碍在强声损伤、衰老、Münie‘s’s听力损失中的作用 疾病、耳毒性药物和某些形式的突发性耳聋。内耳血管生理学知识是 这是了解和治疗这些听力疾病的基础，但该领域的探索仍然很少。这个 本实验室的长期目标是确定耳蜗病常见而独特的病理生理机制。 血管--耳蜗血流量的关键神经体液信使、受体和通道 监管，并发现预防和治疗这些听力损失的药物。 我们以前的研究发现，耳蜗螺旋动脉具有独特的血管张力 静息膜电位(RP)调节和神经肌肉传递的调控机制。基座 根据这些发现，本提案设定了以下目标：1)确定 SMA细胞的双峰RP分布及其在缺血/再灌注中的作用机制 引起RP分布和血管紧张素反应的改变；2)测定离子通道(S)和 受体类型(S)，介导候选神经递质(例如，去甲肾上腺素， 乙酰胆碱，CGRP)；3)确定候选神经递质在内源性神经肌肉中的作用 SMA中的变速箱。这些目标将通过使用常规和全细胞的实验来实现 体外血管平滑肌细胞(VSMC)电流和电压钳记录方法 多种方法，如计算建模、血管直径跟踪、一氧化氮产生- 监测、免疫细胞化学、RT-PCR和Western印迹分析。 通过这些研究，我们希望发现关键通道蛋白KIR与其他持久的 膜电流如KATP和Na~+-K~+泵电流，产生双峰RP，从而实现 具有较高的耳蜗血流量自动调节能力。我们还预计，缺血/再灌注治疗 会导致一氧化氮的产生、KATP和KIR的表达上调，从而导致RP群体 移位和血管反应性改变。新型神经肌肉传递与多种药物作用 将被描述为。所获得的知识将提高我们对耳蜗血流量如何的理解。 调节和哪些关键因素导致耳蜗血循环不足，从而有助于更好 预防和治疗血液循环相关的听力损失，甚至心脏病发作和中风。

Summary Blood circulation disturbances contribute to the hearing loss in loud-sound induced trauma, aging, M¿ni¿re's disease, ototoxic drugs and some forms of sudden deafness. Knowledge of inner ear vascular physiology is fundamental to understanding and treating these hearing conditions, but the field remains poorly explored. The long-term goal of this lab is to determine the common and unique patho-physiological mechanisms of cochlear vessels, the key neurohumoral messengers, receptors and channels responsible for cochlear blood flow regulation, and to discover drugs for prevention and treatment of these hearing losses. Our previous studies have found that the cochlear spiral modiolar artery (SMA) has unique vascular tone control mechanisms in resting membrane potential (RP) regulation and neuromuscular transmission. Based on these findings, this proposal sets the following aims: 1) to determine the mechanism and significance that underlie the bi-modal RP distribution of the SMA cells and the mechanism by which ischemia/reperfusion causes the change of the RP distribution and vasotone response; 2) to determine the ion channel(s) and receptor type(s) that mediate the actions of the candidate neurotransmitters (e.g., norepinephrine, acetylcholine, CGRP); 3) to identify the role of candidate neurotransmitters in intrinsic neuromuscular transmission in the SMA. These goals will be achieved through experiments using conventional and whole-cell current- and voltage-clamp recording methods on the in vitro vascular smooth muscle cells (VSMC), plus multiple approaches such as computational modeling, vaso-diameter tracking, nitric oxide production- monitoring, immunocytochemistry, RT-PCR and Western blot analyses. With these studies, we expect to find that the Key channel protein, Kir, co-plays with other persistent membrane currents, such as KATP and Na+-K+-pump currents, to generate the bimodal RP and thus to achieve a high autoregulation capacity of cochlear blood flow. We also anticipate that ischemia/reperfusion treatment will cause up-regulation of nitric oxide production, KATP and Kir expression, and thus cause the RP population shift and the vascular responsiveness change. The novel neuromuscular transmission and various drug effects will be characterized. The knowledge obtained will improve our understanding of how cochlear blood flow is regulated and what are the key factors causing cochlear circulation-deficiency, thus contributing to better prevention and treatment of the circulation-implicated hearing loss, and even the heart attack & stroke.