Serotonin Based Therapeutics in Cerebral Palsy

项目摘要：基于血清素的脑瘫治疗 脑性瘫痪（CP）是一种相对常见的非进展性疾病，导致终身运动功能障碍。最 痉挛型脑瘫是一种常见的脑瘫类型，其特征是肌肉张力过高、无力、反射亢进、随意性降低 (and运动单位的激活，皮质脊髓束的变薄，以及运动单位数量的减少。 单位虽然痉挛性脑瘫的肌肉无力和张力亢进已有很好的记录， 发病机理几乎完全未知。 以前的工作和我们的初步数据从临床前模型的CP表明，运动神经元（MN）显示， 围产期损伤后过度活动，特别是对5-羟色胺（5-HT）的反应。这可能导致或促成 因为阻断5 HT受体可以减轻张力亢进。在发育过程中，自发的神经活动 主要负责在脊髓回路内和脊髓MN之间建立连接， 肌肉和建立在自然发育细胞死亡后存活的MN数量。该提案重点 在关键的发育时间点阻断脊髓5 HT受体，以恢复正常的MN活性， 运动单位功能，并减轻虚弱、张力亢进和反射亢进。在这项研究中，我们将利用一个更大的动物， CP模型（家兔妊娠70-80%时的产前缺氧-缺血[HI]），显示出强烈的运动功能障碍 并且最近已经证明具有CP的临床特征，包括CST变薄和皮质损伤， 反射亢进、肌肉病理和MN数量减少。 目的1：确定产前HI损伤后运动单位的出生后里程碑。从出生到31天 在两种性别的兔子套件中，我们将量化运动单位的异常发育，特别是1）运动 清醒套件中的行为，包括关节扭矩，2）运动神经元/运动单位放电模式的体内记录， 运动单位收缩力和H反射; 3）运动单位解剖发育。意义：时机 治疗（目标3）将在围产期或产后实现运动单位成熟。 目的2：鉴定介导肌张力增高的5-HT受体。在两种性别的新生兔试剂盒（假手术和 HI），我们将使用多种5 HT受体拮抗剂在体外和体内评估受体药理学和剂量依赖性。 受体激动剂和拮抗剂。意义：研究结果将指导目标3中药物治疗的选择。 目的3：评价5 HT拮抗剂治疗。我们将比较围产期和产后的影响 基于目的2的结果，在假手术和HI试剂盒上用β-肾上腺素能拮抗剂和激动剂治疗。治疗 与运动单位的成熟相吻合。我们将在目标1中描述的试剂盒中检查结果。 意义：该目的提供了一种用于减少CP痉挛的新型治疗方法的临床前评价。 我们将使用兔CP模型来评估潜在的治疗方法，以减少产前损伤后的痉挛。 可以研究几种FDA批准的多巴胺能药物，以改善有CP风险的儿童的结局。

Project Summary: Serotonin based therapeutics in cerebral palsy Cerebral palsy (CP) is a relatively common nonprogressive disorder causing lifelong motor dysfunction. The most prevalent type, spastic cerebral palsy, is characterized by muscle hypertonia, weakness, hyperreflexia, less voluntary (and more involuntary) activation of motor units, thinning of the corticospinal tract, and decreased numbers of motor units. While weakness and hypertonia in muscles have been well documented in spastic cerebral palsy, the etiopathogenesis is almost completely unknown. Previous work and our preliminary data from preclinical models of CP show that motoneurons (MNs) show excessive activity after perinatal injury, particularly in response to serotonin (5HT). This is likely causing or contributing to hypertonia since blocking 5HT receptors can alleviate hypertonia. During development, spontaneous neural activity is largely responsible for establishing connectivity within spinal circuits and between spinal MNs and developing muscles and establishing numbers of MNs that survive past natural developmental cell death. This proposal focuses on blockade of spinal 5HT receptors at a critical developmental time point in order to restore normal MN activity / motor unit function, and alleviate weakness, hypertonia, and hyperreflexia. In this study we will utilize a larger animal model of CP (prenatal hypoxia-ischemia [HI] at 70-80% gestation in rabbits), which shows robust motor dysfunction and has recently been demonstrated to have clinical features of CP including thinning of CST and cortical damage, hyperreflexia, muscle pathology, and reduced numbers of MNs. Aim 1: Identify postnatal milestones in motor units following prenatal HI injury. From birth to 31 days of age in rabbit kits of both sexes, we will quantify aberrant development of motor units, specifically 1) motor behavior in awake kits, including joint torque, 2) in vivo recording of motoneuron / motor unit firing patterns, motor unit contraction force, and H reflex and 3) anatomical development of motor units. Significance: Timing of treatment (Aim 3) will be delivered motor unit maturation, either perinatally or postnatally. Aim 2: Identify 5HT receptor(s) mediating hypertonia. In newborn rabbit kits of both sexes (sham and HI), we will assess receptor pharmacology and dose dependency in vitro and in vivo using a variety 5HT receptor agonists and antagonists. Significance: Findings will guide choice of drug treatment in Aim 3. Aim 3: Evaluate treatment with a 5HT antagonist. We will compare effects of perinatal and postnatal treatment with a serotonergic antagonist and agonist on sham and HI kits based on results of Aim 2. Treatment coincides with maturation of motor units. We will examine the outcome in kits as described in Aim 1. Significance: This aim provides a preclinical evaluation of novel therapeutic for reduction of spasticity in CP. We will use the rabbit model of CP to evaluate potential therapies to reduce spasticity after prenatal injury. Several FDA-approved serotonergic drugs could be investigated to improve outcomes in kids at risk of CP.