Abstract：
Sensory neuron hyperexcitability is a critical driver of pathological pain and can result from axon damage, inflammation, or neuronal stress. G-protein coupled receptor signaling can induce pain amplification by modulating the activation of Trp-family ionotropic receptors and voltage-gated ion channels. Here, we sought to use calcium imaging to identify novel inhibitors of the intracellular pathways that mediate sensory neuron sensitization and lead to hyperexcitability. We identified a novel stimulus cocktail, consisting of the SSTR2 agonist L-054,264 and the S1PR3 agonist CYM5541, that elicits calcium responses in mouse primary sensory neurons in vitro as well as pain and thermal hypersensitivity in mice in vivo. We screened a library of 906 bioactive compounds and identified 24 hits that reduced calcium flux elicited by L-054,264/CYM5541. Among these hits, silymarin, a natural product derived from milk thistle, strongly reduced activation by the stimulation cocktail, as well as by a distinct inflammatory cocktail containing bradykinin and prostaglandin E2. Silymarin had no effect on sensory neuron excitability at baseline, but reduced calcium flux via Orai channels and downstream mediators of phospholipase C signaling. In vivo, silymarin pretreatment blocked development of adjuvant-mediated thermal hypersensitivity, indicating potential use as an anti-inflammatory analgesic.
摘要：
感觉神经元兴奋过度是病理性疼痛的关键驱动因素，可能由轴突损伤引起，炎症,或神经元应激。G蛋白偶联受体（GPCR）信号可以通过调节Trp家族离子型受体和电压门控离子通道的激活来诱导疼痛放大。这里,我们试图利用钙成像技术来鉴定介导感觉神经元致敏并导致过度兴奋的细胞内通路的新型抑制剂.我们确定了一种由SST2R激动剂L-054,264组成的新型刺激混合物，和CYM5541，一种S1PR3激动剂，在体外引起小鼠初级感觉神经元的钙反应以及在体内引起小鼠的疼痛和热超敏反应。我们筛选了906种生物活性化合物的文库,并鉴定了由L-054,264/CYM5541引起的降低钙通量的24个命中。在这些热门歌曲中，水飞蓟素,从水飞蓟中提取的天然产物，强烈减少了刺激鸡尾酒的激活，以及含有缓激肽和前列腺素E2的独特炎症混合物。水飞蓟素在基线时对感觉神经元兴奋性没有影响，但是通过Orai通道和磷脂酶C信号传导的下游介质减少了钙通量。在体内,水飞蓟素预处理阻断佐剂介导的热超敏反应的发展，表明作为抗炎镇痛药的潜在用途。
