Regulation of κ-Opioid Receptor Signaling in Peripheral Sensory Neurons In Vitro and In Vivo
Regulation of κ-Opioid Receptor Signaling in Peripheral Sensory Neurons In Vitro and In Vivo
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DOI：
10.1124/jpet.110.177493
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发表时间：
2011-07-01
影响因子：
3.5
通讯作者：
Clarke, William P.
中科院分区：
文献类型：
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作者：
Berg, Kelly A.;Rowan, Matthew P.;Clarke, William P.
人们对了解外周阿片受体的调节以避免全身应用阿片类止痛药引起的中枢神经系统副作用有相当大的兴趣。在这里，我们研究了kappa-阿片受体(KOR)对体外培养的大鼠初级感觉神经元的调节作用，以及在热过敏大鼠模型中的作用。在基础条件下，应用KOR激动剂反式-(1S，2S)-3，4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl)cyclohexyl])苯乙酰胺盐酸盐(U50488)在体外不抑制腺酰环化酶(AC)活性，也不抑制降钙素基因相关肽(CGRP)的释放，也不抑制体内热性痛觉过敏。然而，缓激肽(BK)预处理15min后，U50488可抑制AC活性、CGRP释放和热痛。5-羟色胺1或神经肽Y-1受体激动剂对AC的抑制和U50488对细胞外信号调节激酶活性的刺激不需要BK预先处理。KOR拮抗剂Nor-binaltorphimine在体内外均可阻断U50488在BK诱导的组织中的作用。BK在体外的作用可被吲哚美辛或双吲哚马来酰亚胺阻断，提示花生四烯酸(AA)代谢产物和蛋白激酶C(PKC)激活介导了BK对KOR系统的调节。此外，U50488在BK处理组织中的作用可被可溶性整合素阻断肽(GRGDSP)阻断，但不能被非活性反向序列肽(GDGRSP)阻断，这表明除了AA和PKC外，RGD结合的整合素还参与了对U50488应答的KOR信号的调节。了解外周KOR激动剂疗效调节的机制可能有助于改进治疗疼痛的药物疗法，减少不良反应。
There is considerable interest in understanding the regulation of peripheral opioid receptors to avoid central nervous system side effects associated with systemically administered opioid analgesics. Here, we investigated the regulation of the kappa-opioid receptor (KOR) on rat primary sensory neurons in vitro and in a rat model of thermal allodynia. Under basal conditions, application of the KOR agonist trans-(1S, 2S)-3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl)cyclohexyl] benzeneacetamide hydrochloride hydrate (U50488) did not inhibit adenylyl cyclase (AC) activity nor release of calcitonin gene-related peptide (CGRP) in vitro and did not inhibit thermal allodynia in vivo. However, after 15-min pretreatment with bradykinin (BK), U50488 became capable of inhibiting AC activity, CGRP release, and thermal allodynia. Inhibition of AC by 5-hydroxytryptamine 1 or neuropeptide Y-1 receptor agonists and stimulation of extracellular signal-regulated kinase activity by U50488 did not require BK pretreatment. The effect of U50488 in BK-primed tissue was blocked by the KOR antagonist nor-binaltorphimine both in vitro and in vivo. The effect of BK in vitro was blocked by either indomethacin or bisindolylmaleimide, suggesting that an arachidonic acid (AA) metabolite and protein kinase C (PKC) activation mediate BK-induced regulation of the KOR system. Furthermore, the effect of U50488 in BK-treated tissue was blocked by a soluble integrin-blocking peptide (GRGDSP), but not the inactive reverse sequence peptide (GDGRSP), suggesting that, in addition to AA and PKC, RGD-binding integrins participate in the regulation of KOR signaling in response to U50488. Understanding the mechanisms by which peripheral KOR agonist efficacy is regulated may lead to improved pharmacotherapy for the treatment of pain with reduced adverse effects.