FUNCTIONAL ANALYSIS OF CALCIUM CHANNEL MUTATIONS IN TRIGEMINAL NOCICEPTION

三叉神经伤害钙通道突变的功能分析

• 批准号: 7812016
• 负责人: YUQING CAO
• 金额: $ 22.57万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-05-01 至 2012-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7812016
• 关键词: Accounting; Address; Affect; Afferent Neurons; Biological; Calcium Channel; Cells; Cervical; Classic Migraine; Coculture Techniques; Coupling; Defect; Dendrites; Dependence; Disease; Dyes; Employee Strikes; Experimental Models; Familial Hemiplegic Migraine; Functional disorder; Future; Generations; Genes; Genetic Predisposition to Disease; Headache; Healthcare Systems; Human; Inherited; Investigation; Knock-out; Lead; Light; Methods; Migraine; Modeling; Mus; Mutation; Neurobiology; Neurons; Nociception; Pain; Palliative Care; Pathway interactions; Patients; Play; Point Mutation; Population; Posterior Horn Cells; Presynaptic Terminals; Preventive; Process; Property; Rare Diseases; Relative (related person); Research; Role; Signal Transduction; Structure of trigeminal ganglion; Synapses; Synaptic Transmission; System; Testing; Trigeminal System; Up-Regulation; Work; dorsal horn; drug development; gain of function; hemiparesis; insight; loss of function; mutant; neuronal cell body; neuronal excitability; neurotransmission; neurotransmitter release; patch clamp; postsynaptic; public health relevance; research study; transmission process; voltage

Description (provided by applicant): Migraine is one of the most common neurovascular disorders with noticeable genetic predisposition. Understanding the mechanisms of migraine will lead to more specific treatments. Familial Hemiplegic Migraine (FHM), a rare hereditary form of migraine with aura and hemiparesis, serves as a good model for exploring migraine pathophysiology. The gene for FHM type 1 (FHM-1) encodes the pore-forming 1A subunit of P/Q- type voltage-gated Ca2+ channels - a key player in supporting voltage-dependent Ca2+ entry that is critical for neurotransmitter release at presynaptic terminals and postsynaptic Ca2+ signaling in soma and dendrites. The discovery of multiple 1A mutations in FHM-1 patients provides a platform for elucidating the mechanism underlying FHM-1 as well as migraine in general. We have initiated experiments to explore the effects of T666M, the most frequently occurring FHM-1 mutation, on voltage-dependent Ca2+ influx in neurons from the trigeminal nociceptive pathway responsible for headache pain generation. Our preliminary studies indicate that T666M results in a decrease of Ca2+ influx through P/Q- type channels in cultured neurons from trigeminal ganglion as well as cervical dorsal horn. Interestingly, a consequent increase of low-voltage gated T-type current is only observed in the small peptidergic trigeminal ganglion neurons. The research objective of this proposal is to further investigate the functional consequences of the T666M mutation in trigeminal ganglion and dorsal horn neurons. We hypothesize that loss-of-function FHM-1 mutations as represented by T666M may increase the gain of trigeminal nociceptive circuitry via two possible scenarios: 1) increasing the excitability of trigeminal primary afferent neurons and 2) preferentially weakening the inhibitory synaptic transmission at cervical/medullary dorsal horn. In the first aim, we will examine the effect of T666M mutant channels on neuronal excitability using current clamp recordings. The second aim of the proposal addresses how T666M mutant channels affect synaptic transmission from nociceptive neurons. In addition, we will use tottering, mice with a loss-of-function 1A mutation, as experimental model to test the effect of defect P/Q-type channels on the excitability and neurotransmission of trigeminal nociceptive neurons. Together, these experiments will not only increase our understanding of the contribution of voltage-gated Ca2+ channels to FHM-1 and general migraine pathophysiology; but also shed light on the mechanisms underlying other forms of headache. Importantly, these studies will lay ground work for future investigations of the functional consequences of FHM-1 mutations in the context of trigeminal nociceptive circuit as well as from a systems neurobiology perspective. PUBLIC HEALTH RELEVANCE: Migraine is one of the most common neurovascular disorders and an enormous burden to the healthcare system. Understanding the disease mechanisms will greatly facilitate drug development for both preventive and palliative therapies of migraine. Multiple mutations in human P/Q-type voltage-gated Ca2+ channels have been associated with familial hemiplegic migraine type 1 (FHM-1) - a hereditary form of migraine. We propose to study the functional consequences of T666M, the most frequently occurred mutation, as a gateway towards understanding the mechanisms underlying migraine headache.

描述（由申请人提供）：偏头痛是具有明显遗传易感性的最常见神经血管疾病之一。了解偏头痛的机制将导致更具体的治疗方法。家族性偏瘫偏头痛（FHM）是一种罕见的遗传性偏头痛，具有光环和偏瘫，是探索偏头痛病理生理学的良好模型。 FHM 1型（FHM-1）的基因编码P/Q-类型电压门控的Ca2+通道的孔形成1A亚基 - 支持电压依赖性CA2+进入的关键参与者，这对于神经释放剂对神经递质的释放至关重要，这对于在somaptic dernaptic distinals and Synaptic Ca2+ Somiental insynaptic Ca2+信号+信号+ somming insa和denderitient中都是至关重要的。 FHM-1患者中多个1A突变的发现提供了一个平台，以阐明FHM-1和偏头痛的机制。我们已经开始了实验，以探索T666M（最常见的FHM-1突变）对来自三叉神经伤害性途径的神经元依赖电压依赖性Ca2+涌入的影响。我们的初步研究表明，T666M导致三叉神经节和宫颈背角的培养神经元中的P/Q-型通道减少Ca2+流入。有趣的是，仅在小型肽类神经节神经元中观察到低压门控T型电流的增加。该提案的研究目标是进一步研究三叉神经节和背角神经元中T666M突变的功能后果。我们假设通过T666M代表的功能丧失的FHM-1突变可能会通过两种可能的情况增加三叉神经伤害感受回路的增益：1）增加三叉神经初级传入神经元的兴奋性和2）优先弱化的抑制性突触传播在宫颈/髓质的角下的抑制性突触传播。在第一个目标中，我们将使用当前的夹具记录来检查T666M突变通道对神经元兴奋性的影响。该提案的第二个目的是针对T666M突变通道如何影响伤害性神经元的突触传播。此外，我们将使用具有功能丧失1A突变的小鼠作为实验模型，以测试缺陷P/Q-Type通道对三叉神经受害神经元的兴奋性和神经传递的影响。总之，这些实验不仅会增加我们对电压门控Ca2+通道对FHM-1和一般偏头痛病理生理学的贡献的理解。而且还阐明了其他形式的头痛的机制。重要的是，这些研究将为未来研究FHM-1突变的功能后果，并从系统神经生物学的角度研究FHM-1突变的功能后果。公共卫生相关性：偏头痛是最常见的神经血管疾病之一，也是医疗保健系统的巨大负担。了解疾病机制将极大地促进偏头痛的预防和姑息治疗的药物开发。人类P/Q-Type电压门控Ca2+通道中的多个突变与家族性偏瘫偏头痛1型（FHM-1） - 一种偏头痛的遗传形式。我们建议研究最常见的突变T666M的功能后果，以了解了解偏头痛的机制的门户。