Membrane microviscosity modulates μ-opioid receptor conformational transitions and agonist efficacy
Membrane microviscosity modulates μ-opioid receptor conformational transitions and agonist efficacy
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DOI：
10.1046/j.1471-4159.1999.0730289.x
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发表时间：
1999-07-01
影响因子：
4.7
通讯作者：
Remmers, AE
中科院分区：
文献类型：
--
作者：
Emmerson, PJ;Clark, MJ;Remmers, AE
膜微粘度对μ-阿片激动剂和拮抗剂结合的影响，以及激动剂的功效，在由SH-SY 5 Y细胞和稳定表达大鼠μ-阿片受体（C6 μ）的C6神经胶质瘤细胞系制备的膜中进行了检查。向细胞膜中加入胆固醇半琥珀酸酯（CHS）可增加膜微粘度，降低钠和鸟嘌呤核苷酸对完全激动剂舒芬太尼和[D-Ala（2），N-MePhe（4），Gly-ol（5）]脑啡肽（DAMGO）对μ阿片受体亲和力的抑制作用。拮抗剂[H-3]纳洛酮和[H-3]二丙诺啡和部分激动剂纳布啡的结合不受CHS的影响。CHS对激动剂结合的影响被随后加入顺式异油酸逆转，表明CHS的影响是膜微粘度增加的结果，而不是特定的甾醇-受体相互作用。CHS的加入使DAMGO刺激鸟苷-5 ′-O-（3-S-35]硫代）三磷酸结合的效力增加了四倍，而纳布啡的效力不受影响。然而，与对照膜相比，在CHS处理的膜中，纳布啡相对于完全激动剂DAMGO的效力显著增加。膜硬化也导致增加的效力，部分激动剂哌替啶，profadol，布托啡诺相对于DAMGO的激动剂刺激的GTdR活性在控制和CHS-改性膜测量。这些发现支持膜微粘度在受体介导的G蛋白活化中的调节作用。
The influence of membrane microviscosity on mu-opioid agonist and antagonist binding, as well as agonist efficacy, was examined in membranes prepared from SH-SY5Y cells and from a C6 glioma cell line stably expressing the rat mu-opioid receptor (C6 mu). Addition of cholesteryl hemisuccinate (CHS) to cell membranes increased membrane microviscosity and reduced the inhibitory effect of sodium and guanine nucleotides on the affinity of the full agonists sufentanil and [D-Ala(2),N-MePhe(4),Gly-ol(5)]enkephalin (DAMGO) for the mu-opioid receptor. Binding of the antagonists [H-3]naltrexone and [H-3]diprenorphine and the partial agonist nalbuphine was unaffected by CHS. The effect of CHS on agonist binding was reversed by subsequent addition of cis-vaccenic acid, suggesting that the effect of CHS is the result of increased membrane microviscosity and not a specific sterol-receptor interaction. CHS addition increased the potency of DAMGO to stimulate guanosine-5'-O-(3-S-35]thio)triphosphate binding by fourfold, whereas the potency of nalbuphine was unaffected, However, nalbuphine efficacy relative to that of the full agonist DAMGO was strongly increased in CHS-treated membranes compared with that in control membranes. Membrane rigidification also resulted in an increased efficacy for the partial agonists meperidine, profadol, and butorphanol relative to that of DAMGO as measured by agonist-stimulated GTPase activity in control and CHS-modified membranes. These findings support a regulatory role for membrane microviscosity in receptor-mediated G protein activation.