PKCβ Inhibitors Attenuate Amphetamine-Stimulated Dopamine Efflux
PKCβ Inhibitors Attenuate Amphetamine-Stimulated Dopamine Efflux
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DOI：
10.1021/acschemneuro.6b00028
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发表时间：
2016-06-01
影响因子：
5
通讯作者：
Gnegy, Margaret E.
中科院分区：
文献类型：
--
作者：
Zestos, Alexander G.;Mikelman, Sarah R.;Gnegy, Margaret E.
安非他明滥用影响着超过 1300 万人，目前还没有普遍接受的治疗安非他明成瘾的方法。安非他明作为多巴胺转运蛋白的底物并逆转转运蛋白，导致细胞外多巴胺增加。在苯丙胺存在的情况下，蛋白激酶 C (PKC beta) 的 β 亚基的激活可通过促进多巴胺的逆向转运和内化 D2 自身受体来增强细胞外多巴胺。我们之前证明 PKC β 抑制剂可在体外阻断大鼠纹状体突触体中安非他明刺激的多巴胺流出。在这项研究中，我们利用活体行为大鼠的体内微透析来评估 PKC β 抑制剂 enzastaurin 和 ruboxistaurin 对安非他明刺激的运动以及单胺及其代谢物增加的影响。用1μM enzastaurin 或1μM ruboxistaurin 向伏核核心灌注30 分钟，可将安非他明诱导的多巴胺及其代谢物3-甲氧基酪胺的流出减少约50%。这些抑制剂还显着降低了安非他明刺激的细胞外去甲肾上腺素水平。与分析物同时测量的安非他明对运动行为的刺激被 PKC β 抑制剂相对减弱。使用稳定同位素标记逆透析程序，我们确定 ruboxistaurin 对多巴胺、去甲肾上腺素、谷氨酸或 GABA 的基础水平没有影响。此外，根据大鼠突触体的测量，PKC β 抑制剂不会改变多巴胺转运蛋白的正常摄取功能。我们的结果支持使用 PKC β 抑制剂来减少安非他明的作用。
Amphetamine abuse afflicts over 13 million people, and there is currently no universally accepted treatment for amphetamine addiction. Amphetamine serves as a substrate for the dopamine transporter and reverses the transporter to cause an increase in extracellular dopamine. Activation of the beta subunit of protein kinase C (PKC beta) enhances extracellular dopamine in the presence of amphetamine by facilitating the reverse transport of dopamine and internalizing the D2 autoreceptor. We previously demonstrated that PKC beta inhibitors block amphetamine-stimulated dopamine efflux in synaptosomes from rat striatum in vitro. In this study, we utilized in vivo microdialysis in live, behaving rats to assess the effect of the PKC beta inhibitors, enzastaurin and ruboxistaurin, on amphetamine-stimulated locomotion and increases in monoamines and their metabolites. A 30 min perfusion of the nucleus accumbens core with 1 mu M enzastaurin or 1 mu M ruboxistaurin reduced efflux of dopamine and its metabolite 3-methoxytyramine induced by amphetamine by approximately 50%. The inhibitors also significantly reduced amphetamine-stimulated extracellular levels of norepinephrine. The stimulation of locomotor behavior by amphetamine, measured simultaneously with the analytes, was comparably reduced by the PKC beta inhibitors. Using a stable isotope label retrodialysis procedure, we determined that ruboxistaurin had no effect on basal levels of dopamine, norepinephrine, glutamate, or GABA. In addition, normal uptake function through the dopamine transporter was unaltered by the PKC beta inhibitors, as measured in rat synaptosomes. Our results support the utility of using PKC beta inhibitors to reduce the effects of amphetamine.