Ca~(2+)/钙调蛋白依赖的蛋白激酶Ⅱ信息通路在DPDPE长时程作用的NG108-15细胞中的作用

目的　观察阿片类依赖时Ca2 + /钙调蛋白依赖的蛋白激酶Ⅱ (CaMKⅡ )信息通路的变化 ,以及Ca2 + /CaMKⅡ信息通路与cAMP水平之间的关系。方法　以NG10 8 15细胞作为体外的细胞模型 ,分别采用竞争性蛋白结合法及放射免疫法、PDE法、γ 3 2 P参入法以及RT PCR测定cAMP水平、钙调蛋白 (CaM)活性、CaMKⅡ活性和mDOR的mRNA表达水平的变化。结果　DPDPE长时程作用NG10 8 15细胞 ,cAMP水平升高 ,形成阿片依赖 ;细胞CaM活性和CaMKⅡ活性也升高 ,该升高可被CaM拮抗剂W 7所抑制 ,而CaMKⅡ活性的升高可被CaMKⅡ特异性抑制剂KN 6 2所抑制。W 7或KN 6 2可抑制阿片依赖导致的细胞cAMP水平的升高。阿片依赖时 ,加入纳洛酮诱发戒断 ,CaM活性、CaMKⅡ活性进一步增高。而在阿片依赖时 ,δ阿片受体的mRNA表达水平无明显变化。结论　Ca2 + /钙调蛋白依赖的蛋白激酶Ⅱ信息通路可通过调节cAMP水平参与阿片依赖的机制。

Effects of Ca2+/ calmodulin dependent protein kinase Ⅱ signal pathway in DPDPE long term treatment NG108-15 cells

AIM To observe the change of Ca 2+ /calmodulin dependent protein kinaseⅡ (CaMKⅡ) signal pathway in opioids dependent NG108-15 cells and the relationships between Ca 2+ /calmodulin dependent protein kinaseⅡ (CaMKⅡ) signal pathway and cAMP accumulation. METHODS NG108-15 cells were used as an in vitro model system. Competitive protein binding assay and radioimmunoassay were used to examine the intracellular cAMP accumulation. Calmodulin activity was assayed by PDE method. CaMKⅡ activity was assayed by γ- 32 P incorporation of syntide-2. mRNA expression of mDOR was measured by RT-PCR. RESULTS DPDPE long-term treatment also increased cAMP accumulation, and resulted in opioids dependence in NG108-15 cells; DPDPE long-term treatment increased calmodulin activity and CaMKⅡ activity in NG108-15 cells. Specific calmodulin antagonist W-7 was found to inhibit significantly the elevation of calmodulin and CaMKⅡ activity which resulted from DPDPE long-term treatment, and CaMKⅡ inhibitor KN-62 also inhibited elevation of CaMKⅡ activity by DPDPE long-term treatment. DPDPE long-term treatment increased cAMP accumulation, when W-7 or KN-62 was added at the same time, cAMP accumulation decreased. When naloxone was added to NG108-15 cells which were long-term treated by DPDPE, calmodulin and CaMKⅡactivity increased more. mRNA level of mDOR did not change significantly in opioids dependent NG108-15 cells. CONCLUSION Ca 2+ /CaMKⅡ signal pathway was involved in the mechanisms of opioids dependence through regulating cAMP level when DPDPE is long-term administered to NG108-15 cells.