The Effect of Protein Kinase C and G Protein-Coupled Receptor Kinase Inhibition on Tolerance Induced by μ-Opioid Agonists of Different Efficacy
The Effect of Protein Kinase C and G Protein-Coupled Receptor Kinase Inhibition on Tolerance Induced by μ-Opioid Agonists of Different Efficacy
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DOI：
10.1124/jpet.109.161455
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发表时间：
2010-03-01
影响因子：
3.5
通讯作者：
Dewey, W. L.
中科院分区：
文献类型：
--
作者：
Hull, L. C.;Llorente, J.;Dewey, W. L.
不同疗效的阿片激动剂引起的耐受和u阿片受体脱敏的机制也不同。本研究旨在探讨抑制蛋白激酶C(PKC)和G蛋白偶联受体激酶(GRK)对不同药效阿片类激动剂体内抗伤害耐受性的影响。使用快速(8小时)耐受诱导模型，其中每个阿片类药物重复给幼鼠服用。然后，在注射了一种激酶抑制剂后，用阿片类药物挑战动物，以确定其对耐受水平的影响。对度冷丁、吗啡或芬太尼的耐受性可被蛋白激酶C抑制剂12-(2-cyanoethyl)-6，7，12，13-tetrahydro-13-methyl-5-oxo-5H-indolo(2，3-a)pyrrolo(3，4-c)carbazole(Go6976)完全逆转。然而，体内对[D-Ala(2)，N-Me-Phe(4)，Gly(5)-ol]-Enkephalin(DAMGO)的耐受性不能被PKC抑制逆转。新型小分子GRK抑制剂β-肾上腺素能受体激酶1抑制剂和2-(8-[(二甲氨基)methyl]-6，7，8，9-tetrahydropyridol[1，2-a]indol-3-yl)-3-(1-methylindol-3-yl)maleimide，RO32-0432)不能逆转对度冷丁、芬太尼或吗啡的耐受性，但能逆转对DAMGO的耐受性。为了将GRK依赖的DAMGO诱导的耐受与Mu-阿片受体脱敏联系起来，我们采用小鼠蓝斑神经元的体外全细胞膜片钳记录，观察到GRK抑制剂可降低DAMGO诱导的Mu-阿片受体脱敏，而PKC抑制剂则不起作用。这些结果表明，中低效MU阿片受体激动剂诱导的耐受依赖于PKC，而高效激动剂DAMGO诱导的耐受依赖于GRK。
Differences in the mechanisms underlying tolerance and mu-opioid receptor desensitization resulting from exposure to opioid agonists of different efficacy have been suggested previously. The objective of this study was to determine the effects of protein kinase C (PKC) and G protein-coupled receptor kinase (GRK) inhibition on antinociceptive tolerance in vivo to opioid agonists of different efficacy. A rapid (8-h) tolerance-induction model was used where each opioid was repeatedly administered to naive mice. Animals were then challenged with the opioid after injection of a kinase inhibitor to determine its effects on the level of tolerance. Tolerance to meperidine, morphine, or fentanyl was fully reversed by the PKC inhibitor 12-(2-cyanoethyl)-6,7,12,13-tetrahydro-13-methyl-5-oxo-5H-indolo(2,3-a)pyrrolo(3,4-c)carbazole (Go6976). However, in vivo tolerance to [D-Ala(2), N-Me-Phe(4), Gly(5)-ol]-enkephalin (DAMGO) was not reversed by PKC inhibition. The novel small-molecule GRK inhibitors beta-adrenergic receptor kinase 1 inhibitor and 2-(8-[(dimethylamino) methyl]-6,7,8,9-tetrahydropyridol[1,2-a]indol-3-yl)-3-(1-methylindol-3-yl)maleimide (Ro 32-0432) did not reverse the tolerance to meperidine, fentanyl, or morphine but did reverse the tolerance to DAMGO. To correlate GRK-dependent DAMGO-induced tolerance with mu-opioid receptor desensitization, we used in vitro whole-cell patch-clamp recording from mouse locus coeruleus neurons and observed that the GRK inhibitors reduced DAMGO-induced desensitization of mu-opioid receptors, whereas the PKC inhibitor had no effect. These results suggest that tolerance induced by low- and moderate-efficacy mu-opioid receptor agonists is dependent on PKC, whereas tolerance induced by the high-efficacy agonist DAMGO is dependent on GRK.