Neuropeptide Y1 Receptor-Expressing Neurons in the Lateral Parabrachial Nucleus in Neuropathic Pain

项目摘要 疼痛是一种复杂的现象，它引起躯体感觉和运动反射反应，并伴有明显的 以及情绪和自主状态的长期变化。虽然剧烈疼痛提供了对组织的保护 损伤，无论是慢性或持久的疼痛，都没有保护功能，而且往往使人丧失行动能力。慢性疼痛 疾病使患者、他们的家人和社会衰弱，因为它降低了生活质量并创造了 每年给美国带来总计超过6300亿美元的巨大财务后果 只有美国一个人。神经病理性疼痛是一种慢性疼痛，由病变或疾病引起 躯体感觉系统，影响7-8%的总人口。然而，神经病理性疼痛不是很好。 对止痛药，包括阿片类药物的反应，以及治疗的替代疗法是绝望的 需要的。神经病理性疼痛的发生和维持的潜在机制很差。 明白了。最近一波备受瞩目的研究表明臂旁核是一种感觉。 痛苦和厌恶的中心。PBN是一种小的、双侧的脑桥结构，长期以来一直被认为是 接收令人担忧的、有害的或具有威胁性的动态平衡信息，如味觉厌恶、伤害感或 危险信号。泰勒(UPitt)和贝利(UPenn)实验室内充满希望的初步数据表明， 谷氨酸能PBN神经元表达神经肽Y(NPY)Y1受体(Npy1r表达) 神经性疼痛的维持性。首先，使用清凉的(丙酮液滴)或轻柔的擦拭(棉签) 周围神经损伤后对小鼠后爪的刺激在 表达Npy1r的PBN神经元。第二，通过药物抑制PBNNpy1r表达的神经元。 NPY Y1GI受体的选择性激动剂减少神经病理性疼痛的行为症状，而 表达Npy1r的神经元的化学激活会产生条件性位置厌恶。第三，应用 热刺激可通过体内纤维评估PBNNpy1r表达神经元的钙瞬变 测光学。这些观察结果为我的中心假设提供了前提，即Npy1r表达 PBN神经元的亚群是神经病理性疼痛行为所必需的。 特定目标1将利用体内纤维光度法和原位杂交来评估PBN的活性 Npy1r在假手术和神经病理性动物中的表达神经元。 特异性目标2将应用体内化学遗传学技术抑制假手术组和假手术组大鼠PBN Npy1r表达的神经元 神经病变动物评估其行为反射(机械和冷)和情感的必要性 (条件性位置偏爱)疼痛的组成部分。 具体目标3将同时检查解剖(解剖追踪)和功能作用(抑制 化学遗传学)对表达PBNNpy1r的脊髓上靶点的传出投射进行分析，以揭示特定的 负责神经病理性疼痛的反射性和情感性成分的神经。

Project Summary Pain is a complex phenomenon that elicits somatosensory and motor reflexive responses together with marked and long-lasting changes in emotional and autonomic states. While acute pain provides protection from tissue damage, chronic or long-lasting pain, provides no protective function and is often incapacitating. Chronic pain conditions are debilitating to patients, their families, and society by reducing quality of life and creating enormous financial consequences that total more than 630 billion USD annually for the United States of America alone. Neuropathic pain is a type of chronic pain that arises from a lesion or disease affecting the somatosensory system and affects 7-8% of the general population. However, neuropathic pain is poorly responsive to analgesic drugs, including opioids, and alternative therapeutics for treatment are desperately needed. The underlying mechanisms of the development and maintenance of neuropathic pain are poorly understood. A recent wave of high-profile publications implicates the parabrachial nucleus (PBN) as a sensory hub for pain and aversion. The PBN is, a small, bilateral, pontine brain structure that has long been known to receive alarming, noxious, or threatening homeostatic information such as taste aversion, nociception, or danger cues. Promising preliminary data within the Taylor (UPitt) and Betley (UPenn) laboratories implicate glutamatergic PBN neurons expressing the neuropeptide Y (NPY) Y1 receptor (Npy1r-expressing) in the maintenance of neuropathic pain. First, application of a cool (acetone droplet) or light rub (cotton swab) stimulus to the hindpaw of a mouse following peripheral nerve injury produces significant Fos activation within Npy1r-expressing PBN neurons. Second, pharmacological inhibition of PBNNpy1r-expressing neurons via a selective agonist for the NPY Y1 Gi receptor reduces behavioral symptoms of neuropathic pain, whereas chemogenetic activation of Npy1r-expressing neurons produces conditioned place aversion. Third, application of a heat stimulus produces calcium transients in PBNNpy1r-expressing neurons assessed via in vivo fiber photometry. These observations provide the premise for my central hypothesis that the Npy1r-expressing subset of PBN neurons are necessary for neuropathic pain-like behaviors. Specific Aim 1 will utilize in vivo fiber photometry and in situ hybridization to assess the activation of PBN Npy1r-expressing neurons in both sham and neuropathic animals. Specific Aim 2 will apply in vivo chemogenetics to inhibit PBN Npy1r-expressing neurons in sham and neuropathic animals to assess their necessity for the behavioral reflexive (mechanical and cold) and affective (conditioned place preference) components of pain. Specific Aim 3 will examine both the anatomy (anatomical tracing) and functional role (inhibitory chemogenetics) of the supraspinal targets of PBNNpy1r-expressing efferent projections to uncover the specific ciruits responsible for both the reflexive and affective components of neuropathic pain.