阿片类药物对NG108-15细胞Ca2+/钙调蛋白依赖的蛋白激酶II信息通路的作用

目的　观察阿片类依赖时Ca²⁺ 钙调蛋白依赖的蛋白激酶II信息通路的变化。方法　以NG108-15细胞作为体外的细胞模型,分别用竞争性蛋白结合法及放射免疫法、PDE法、γ-³² P参入法测定cAMP水平、钙调蛋白(CaM)活性和钙调蛋白依赖的蛋白激酶II(CaMKII)活性。结果　DPDPE作用NG108-15细胞48h可使细胞浆和细胞核CaM和CaMKII活性升高,该变化可被CaM特异性拮抗剂W-7所抑制;CaMKII特异性抑制剂KN-62可抑制CaMKII活性的增高,而对CaM活性无明显影响。DPDPE作用NG108-15细胞48h后,加入纳洛酮,CaM活性、CaMKII活性进一步增高。结论　Ca²⁺ CaMKII信息通路参与了阿片依赖的机制。

EFFECTS OF OPIOIDS ON Ca2+/CALMODULIN DEPENDENT PROTEIN KINASE SIGNAL PATHWAY IN NG108-15 CELLS

AIM: To observe the change of Ca2+/calmodulin dependent protein kinase II (CaMK II) signal pathway in opioid dependent NG108-15 cells. 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. CaMK II activity was assayed by gamma-32 P incorporation of syntide-2. RESULTS: DPDPE long-term treatment increased calmodulin activity and CaMK II activity in both cytoplasm and nucleus of NG108-15 cells. Specific calmodulin antagonist W-7 was found to significantly inhibit the elevation of calmodulin and CaMK II activity which resulted from DPDPE long-term treatment, and CaMK II inhibitor KN-62 also inhibited elevation of CaMK II activity by DPDPE long-term treatment. When naloxone was added to NG108-15 cells which were long-term treated by DPDPE, calmodulin and CaMK II activity increased, indicating that naloxone withdrawal can increase Ca2+/CaMK II pathway activity. CONCLUSION: The results indicate that Ca2+/CaMK II pathway was involved in the mechanisms of opioids dependence when DPDPE was long-term administered to NG108-15 cells.