MOLECULAR MECHANISMS OF THE ITCH SENSATION IN THE SPINAL CORD

描述（由申请人提供）：慢性瘙痒或瘙痒是一种重要的临床问题，没有有效的药物可用。慢性瘙痒的分子和细胞机制还没有被很好地理解和研究。最近在脊髓中发现了首个瘙痒特异性基因胃泌素释放肽受体（GRPR），为研究神经系统瘙痒感觉的分子和细胞基础开辟了道路。本修订补充的目的是分别表征胃泌素释放肽（GRP）及其受体GRPR表达细胞在皮肤、脊髓和大脑中的特性。我们还计划在慢性疼痛状态下检查GRP纤维。为此，将通过敲入法产生GRP-eGFP小鼠和GRPR-eGFP-creERT2小鼠。免疫细胞化学将分析表皮GRP+纤维的神经支配，而GRPR-eGFP神经元是否投射到大脑将通过逆行标记技术确定。GRPR+细胞的分子特性也将通过免疫细胞化学和原位杂交进行分析。这些研究将为我们可视化GRP/GRPR相关的瘙痒神经通路提供重要的遗传和分子工具。GRP+或GRPR+表达细胞的表征将大大加快慢性瘙痒研究的速度。

DESCRIPTION (provided by applicant): Chronic itch or pruritus represents a significant clinical problem for which no effective drugs are available. Molecular and cellular mechanisms of chronic pruritus are not well understood and understudied. Recent identification of the first itch-specific gene, gastrin-releasing peptide receptor (GRPR), in the spinal cord opens the way for studying molecular and cellular basis of itch sensation in the nervous system. The goal of this revision supplement is to characterize the identity of gastrin-releasing peptide (GRP)- and its receptor GRPR- expressing cells in the skin, the spinal cord and the brain, respectively. We also plan to examine GRP fibers in chronic pain states. To this end, GRP-eGFP mice and GRPR-eGFP-creERT2 mice will be generated by a knock-in approach. The innervation of GRP+ fibers in the epidermis will be analyzed by immunocytochemistry, whereas whether GRPR-eGFP neurons project to the brain will be determined by retrograde labeling technique. The molecular identity of GRPR+ cells will also be analyzed by immunocytochemistry and in situ hybridization. The proposed studies should provide excellent genetic and molecular tools essential for us to visualize GRP/GRPR- related itch neuronal pathways. Characterization of GRP+ or GRPR+ expressing cells should greatly expedite the tempo of the research on chronic itch. PUBLIC HEALTH RELEVANCE: Chronic itch or pruritus represents a significant clinical problem for which no effective drugs are available. To understand the neural mechanisms of itch, the neuronal pathways that express the itch receptor, GRPR, and its ligand GRP, will be studied by the generation of GRP-eGFP and GRPR-eGFP-creERT2 mice. The proposed studies will advance our understanding of both central and peripheral neural systems important for itch sensation.