(S)-(+)-氯胺酮通过抑制γ-氨基丁酸 B 型受体与 G 蛋白偶联受体激酶 4 或 5 的相互作用来抑制γ-氨基丁酸 B 型受体介导的信号转导脱敏。

S(+)-ketamine suppresses desensitization of γ-aminobutyric acid type B receptor-mediated signaling by inhibition of the interaction of γ-aminobutyric acid type B receptors with G protein-coupled receptor kinase 4 or 5.

机构信息

Department of Anesthesiology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.

出版信息

Anesthesiology. 2011 Feb;114(2):401-11. doi: 10.1097/ALN.0b013e318204e003.

DOI:10.1097/ALN.0b013e318204e003

PMID:21245733

Abstract

BACKGROUND

Intrathecal baclofen therapy is an established treatment for severe spasticity. However, long-term management occasionally results in the development of tolerance. One of the mechanisms of tolerance is desensitization of γ-aminobutyric acid type B receptor (GABABR) because of the complex formation of the GABAB2 subunit (GB2R) and G protein-coupled receptor kinase (GRK) 4 or 5. The current study focused on S(+)-ketamine, which reduces the development of morphine tolerance. This study was designed to investigate whether S(+)-ketamine affects the GABABR desensitization processes by baclofen.

METHODS

The G protein-activated inwardly rectifying K channel currents induced by baclofen were recorded using Xenopus oocytes coexpressing G protein-activated inwardly rectifying K channel 1/2, GABAB1a receptor subunit, GB2R, and GRK. Translocation of GRKs 4 and 5 and protein complex formation of GB2R with GRKs were analyzed by confocal microscopy and fluorescence resonance energy transfer analysis in baby hamster kidney cells coexpressing GABAB1a receptor subunit, fluorescent protein-tagged GB2R, and GRKs. The formation of protein complexes of GB2R with GRKs was also determined by coimmunoprecipitation and Western blot analysis.

RESULTS

Desensitization of GABABR-mediated signaling was suppressed by S(+)-ketamine in a concentration-dependent manner in the electrophysiologic assay. Confocal microscopy revealed that S(+)-ketamine inhibited translocation of GRKs 4 and 5 to the plasma membranes and protein complex formation of GB2R with the GRKs. Western blot analysis also showed that S(+)-ketamine inhibited the protein complex formation of GB2R with the GRKs.

CONCLUSION

S(+)-Ketamine suppressed the desensitization of GABABR-mediated signaling at least in part through inhibition of formation of protein complexes of GB2R with GRK 4 or 5.

摘要

背景

鞘内注射巴氯芬疗法是治疗严重痉挛的一种既定方法。然而，长期管理偶尔会导致耐受的发展。耐受的机制之一是由于 GABA B 型受体（GABABR）的 GB2R 亚基（GB2R）和 G 蛋白偶联受体激酶（GRK）4 或 5 的复杂形成而导致的脱敏。本研究集中在 S(+)-氯胺酮上，它可减少吗啡耐受的发展。本研究旨在研究 S(+)-氯胺酮是否通过巴氯芬影响 GABABR 脱敏过程。

方法

使用共表达 G 蛋白激活内向整流钾通道 1/2、GABAB1a 受体亚基、GB2R 和 GRK 的非洲爪蟾卵母细胞记录由巴氯芬诱导的 G 蛋白激活内向整流钾通道电流。通过共聚焦显微镜和荧光共振能量转移分析在共表达 GABAB1a 受体亚基、荧光蛋白标记的 GB2R 和 GRK 的乳仓鼠肾细胞中分析 GRK4 和 5 的易位和 GB2R 与 GRK 的蛋白复合物形成。通过共免疫沉淀和 Western blot 分析也确定了 GB2R 与 GRK 的蛋白复合物形成。

结果

在电生理测定中，S(+)-氯胺酮以浓度依赖的方式抑制 GABABR 介导的信号转导脱敏。共聚焦显微镜显示 S(+)-氯胺酮抑制 GRK4 和 5 向质膜易位和 GB2R 与 GRK 的蛋白复合物形成。Western blot 分析还表明 S(+)-氯胺酮抑制了 GB2R 与 GRK 的蛋白复合物形成。