Maturation of Neuronal Function and Adenosine

神经元功能和腺苷的成熟

• 批准号: 6579953
• 负责人: ARUN R. WAKADE
• 金额: $ 6.93万
• 依托单位: WAYNE STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-03-01 至 2003-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6579953
• 关键词: adenosine; calcium flux; cardiac myocytes; chick embryo; developmental neurobiology; potassium channel; sympathetic nervous system; tissue /cell culture

DESCRIPTION (Applicant's abstract): More than 25 years ago we began studying the control of norepinephrine release by using a perfused neuroeffector model and extensively characterized the physiological, pharmacological and biochemical properties of transmitter release. We extended investigations to include mechanisms at the cellular level by developing a model of cultured sympathetic neurons (SN) from chick embryo. We have established that NGF-supported SN take up tritiated norepinephrine (3H-NE), which can be released by physiologically relevant electrical stimulation. SN express classical ion channels, membrane receptors coupled to second messenger systems and Ca2+-dependent, regulated transmitter release. Agents which affect voltage-dependent Ca2+ entry or second messenger levels affect 3H-NE release in the expected manner. Thus, chick SN in culture are an excellent model of SN in vivo. However, we have noted three surprising and important differences in release properties in SN in culture compared to their counterparts in perfused organs. First, background release of transmitter in the non-stimulation period is low in sympathetic effector organs, but relatively high in cultured SN. Second, electrically evoked release is proportional to stimulation frequency in intact organs, but in cultured SN maximum release occurs at low frequency and does not increase with frequency. Third, the K+ channel blocker tetraethylammonium (TEA) greatly enhances release in neuroeffector organs, but has little effect on evoked release of 3H-NE in cultured SN. However, these abnormal release properties can be corrected when SN are co-cultured with cardiac cells. We have further demonstrated that cardiac cells cause a change in voltage-dependent Ca2+ entry and/or handling in neuritic regions of SN (sites of transmitter release) and modulate K+ currents in a manner which accounts for the changes in 3H-NE release properties. Most recently, we have discovered that chronic treatment of SN with adenosine (Ado) mimicks some effects of cardiac cells on SN release properties. Thus, Ado may well be the agent released by cardiac cells and responsible for modulation of Ca2+ handling and transmitter release in co-cultured SN. This proposal is intended to test this hypothesis and establish a new physiological role for Ado as a trophic molecule necessary for functional maturation of SN during development.

描述（申请人的摘要）：25年前我们开始学习 通过使用灌注神经反应器模型来控制去甲肾上腺素的释放 并广泛地表征了生理，药理和 发射器释放的生化特性。我们将调查扩展到 通过开发培养的模型来包括细胞水平的机制 来自雏鸡胚胎的交感神经元（SN）。我们已经确定 NGF支持的SN接管了tri的去甲肾上腺素（3H-NE），可以是 通过生理上相关的电刺激发布。 SN Express 经典的离子通道，膜受体与第二质会系统耦合 和Ca2+依赖性的，调节的发射器释放。影响的代理 电压依赖性CA2+进入或第二会员水平影响3H-NE释放 预期的方式。因此，培养中的小鸡SN是SN的出色模型 体内。但是，我们注意到三个令人惊讶和重要的差异 与其灌注中的对应物相比 器官。首先，在非刺激期间发射器的背景释放 相同的效应器官较低，但培养的SN相对较高。 其次，电诱发的释放与刺激频率成正比 完整的器官，但在培养的SN最大释放中发生在低频和 不会随频率增加。第三，K+通道阻滞剂 四乙基铵（TEA）大大增强了神经反胶器官的释放，但 对培养的SN中的3H-NE释放几乎没有影响。但是，这些 当SN与SN共同培养时，可以纠正异常的释放特性 心脏细胞。我们进一步证明心脏细胞会导致变化 在依赖电压的Ca2+进入和/或SN的神经区域中 （发射机释放的位点）和以一种方式调节K+电流的方式 说明3H-NE释放属性的变化。最近，我们有 发现用腺苷（ADO）的慢性治疗Mimicks一些 心脏细胞对SN释放性能的影响。因此，Ado很可能是 心脏细胞释放的代理，负责调节Ca2+处理 并在共培养的SN中释放发射机。该建议旨在测试 这个假设并确立了ADO作为营养的新生理作用 开发过程中SN功能成熟所需的分子。