Impairment of Spinal Development in Cerebral Palsy

Quinlan，Katharina项目摘要 本项目追求的假设是，在痉挛性脑瘫（CP）的个人，初级传入， 去极化（PAD）是Ia类传入神经的一种突触前调制，可导致肌张力增高、反射亢进 和反射辐射。我们最近发现，伤害感受器的自发性紧张性活动有助于 垫.最近来自CP的大型动物模型的证据表明，伤害感受器发芽存在沿着更多的 PAD和反射照射。我们建议在有CP和没有CP的人以及兔子中进行平行研究， 产前缺氧缺血（HI）在70%妊娠。兔HI模型显示痉挛性CP的特征，包括 皮质中的细胞死亡、白色物质损伤、皮质脊髓束变薄、肌肉僵硬、反射亢进， 反射照射，以及与痉挛性CP一致的肌肉结构变化。本研究将调查 伤害性传入扩张影响家兔和人类PAD的机制，并测试了 经皮神经刺激（TENS）减轻家兔和人痉挛状态的有效性。目的 1：比较HI/CP中伤害性驱动与GABA Aaxo神经元和PAD的关系。脊髓皮质脊髓神经支配 GABAaxo神经元因发育损伤而减弱。我们假设这会导致 伤害感受器神经支配的GABA Aaxo神经元和增加幅度的伤害感受器驱动的PAD，然后 增加节段间Ia传入传导和反射照射。因此，PAD将在 患有CP的人通过CST和其他已知激活PAD的感觉通路使用H反射的条件反射， 并利用离体兔脊髓，刺激感觉和下行通路和药理学。 预期结果：HI/CP中伤害感受器驱动的PAD和反射照射将更大。目标2：量化 在HI/CP中，伤害性突触接触到GABA Aaxo神经元。伤害性扩张发生在CP/HI， 潜在地增加GABA Aaxo神经元上的突触，与目标1一致。我们假设在HI/CP中， 伤害感受器和GABA Aaxo神经元之间的额外突触伴随着较少的CST接触。我们 将定量兔和死后人体组织中的CGRP+ -GAD 2+接触和CST-GAD 2+接触 采用染料标记和免疫组织化学（IHC）在兔中进行。预期结果： CP/HI将延伸到驱动异常PAD的GABA Aaxo神经元上。目的3：伤害感受器的治疗性阻断。 TENS似乎减少伤害感受器的神经传递，可能通过阿片类和5 HT 1D受体。我们 假设在CP/ HI中，使用腰骶TENS将减少伤害感受器驱动的PAD、反射亢进和 反射辐射通过涉及脊髓阿片样物质和5 HT 1D受体激活的机制，可能 通过激活脑干通路。腰骶部TENS将在兔子和人类中进行测试， 减少痉挛的能力。在兔子中，TENS的作用机制将在 体内鞘内和体外测定1）5 HT 1D 2）α 5 GABAA和3）阿片受体的参与。 预期结果：TENS将减少反射照射/痉挛。

Quinlan, Katharina Project Summary This project pursues the hypothesis that in individuals with spastic cerebral palsy (CP), primary afferent depolarization (PAD), a type of presynaptic modulation of Ia afferents, contributes to hypertonia, hyperreflexia and reflex irradiation. We have recently shown that spontaneous tonic activity of nociceptors contributes to PAD. Recent evidence from a large animal model of CP shows nociceptor sprouting is present along with more PAD and reflex irradiation. We propose parallel studies in people with and without CP and rabbits after prenatal hypoxia-ischemia (HI) at 70% gestation. The rabbit HI model shows hallmarks of spastic CP including cell death in the cortex, white matter injury, thinning of the corticospinal tracts, muscle stiffness, hyperreflexia, reflex irradiation, and changes in muscle architecture consistent with spastic CP. This study will investigate mechanisms by which nociceptive afferent expansion influences PAD in rabbits and humans and tests the effectiveness of transcutaneous nerve stimulation (TENS) to reduce spasticity in both rabbits and people. AIM 1: Compare nociceptive drive to GABAaxo neurons and PAD in HI/CP. Corticospinal innervation of spinal GABAaxo neurons is weakened by developmental injury. We hypothesize that this results in expanded nociceptor innervation of GABAaxo neurons and increased amplitude of nociceptor driven PAD, which then increases intersegmental Ia afferent conduction and reflex irradiation. Therefore, PAD will be measured in people with CP using conditioning of the H reflex by CST and other sensory pathways known to activate PAD, and using the in vitro rabbit spinal cord, stimulation of sensory and descending pathways and pharmacology. Expected outcome: Nociceptor-driven PAD and reflex irradiation will be larger in HI/CP. AIM 2: Quantify nociceptive synaptic contacts onto GABAaxo neurons in HI/CP. Nociceptive expansion occurs in CP/HI, potentially increasing synapses onto GABAaxo neurons, consistent with Aim 1. We hypothesize in HI/CP, additional synapses between nociceptors and GABAaxo neurons are concomitant with fewer CST contacts. We will quantify CGRP+ - GAD2+ contacts in rabbits and postmortem human tissue and CST-GAD2+ contacts using dye labeling and immunohistochemistry (IHC) in rabbits. Expected outcome: Nociceptor expansion in CP/HI will extend onto GABAaxo neurons driving aberrant PAD. AIM 3: Therapeutic blockade of nociceptors. TENS appears to reduce nociceptor neurotransmission, possibly via opioid and 5HT1D receptors. We hypothesize that in CP/ HI, use of lumbosacral TENS will reduce nociceptor-driven PAD, hyperreflexia, and reflex irradiation through a mechanism involving activation of spinal opioid and 5HT1D receptors, possibly through activation of a brainstem pathway. Lumbosacral TENS will be tested in rabbits and humans for its ability to reduce spasticity. In rabbits, mechanisms of action of TENS will be pharmacologically dissected in vivo intrathecally and in vitro to determine involvement of 1) 5HT1D 2) α5GABAA and 3) opioid receptors. Expected outcome: TENS will reduce reflex irradiation / spasticity.