Neuroscience Center and Institute of Biomedicine/Anatomy, Biomedicum Helsinki, P.O. Box 63 (Haartmaninkatu 8), FIN-00014 University of Helsinki, Finland.
Neurosci Lett. 2011 Sep 26;503(1):31-6. doi: 10.1016/j.neulet.2011.08.002. Epub 2011 Aug 7.
Ethanol and other addictive drugs affect many intracellular phosphorylation and dephosphorylation cascades. These cascades are thought to be highly important in the regulation of neuronal activity. The present experiments characterized the regulation of three key signaling molecules, DARPP-32 (dopamine and cAMP regulated phosphoprotein, 32kDa), Akt kinase and ERK1/2 (extracellular signal-regulated kinase 1 and 2) in ethanol-preferring AA (Alko, alcohol) and ethanol-avoiding ANA (Alko, non-alcohol) rat lines. Radioactive in situ hybridization was used in drug naïve animals and Western blotting after acute ethanol administration in striatum, hippocampus and prefrontal cortex. The mRNA levels of DARPP-32 in striatal areas were higher in ANA rats than in AA rats. There was no difference in the striatal enriched phosphatase (STEP61), the downstream target of DARPP-32 expression between the rat lines. Ethanol (1.5g/kg) increased phosphorylation of DARPP-32 at threonine 34 in both AA and in ANA rats indicating that acute ethanol activates DARPP-32 similarly in these rat lines. The expression of Akt kinase was higher in the CA1 of hippocampus in ANA than in AA rats and acute ethanol activated Akt in hippocampus in ANA but not in AA rats. No significant alterations in the regulation of ERK1/2 were found in either rat line. Our findings suggest that DARPP-32 and Akt are regulated by ethanol and differences in the regulation of these molecules might contribute to the dramatically different ethanol drinking patterns seen in AA and ANA rats.
乙醇和其他成瘾药物会影响许多细胞内的磷酸化和去磷酸化级联反应。这些级联反应被认为在调节神经元活动方面非常重要。本实验对三种关键信号分子 DARPP-32（多巴胺和 cAMP 调节磷酸蛋白，32kDa）、Akt 激酶和 ERK1/2（细胞外信号调节激酶 1 和 2）在乙醇偏好性 AA（Alko，酒精）和乙醇回避性 ANA（Alko，非酒精）大鼠品系中的调节进行了描述。在纹状体、海马和前额叶皮层，在药物未处理的动物中使用放射性原位杂交，在急性乙醇给药后进行 Western 印迹。ANA 大鼠纹状体区域的 DARPP-32 mRNA 水平高于 AA 大鼠。大鼠品系之间的 DARPP-32 表达的下游靶标纹状体丰富磷酸酶（STEP61）没有差异。乙醇（1.5g/kg）增加了 AA 和 ANA 大鼠中 DARPP-32 丝氨酸 34 位点的磷酸化，表明急性乙醇在这些大鼠品系中同样激活了 DARPP-32。ANA 大鼠海马 CA1 区的 Akt 激酶表达高于 AA 大鼠，急性乙醇激活了 ANA 大鼠的海马 Akt，但没有激活 AA 大鼠的海马 Akt。在两种大鼠品系中均未发现 ERK1/2 调节的显著变化。我们的研究结果表明，DARPP-32 和 Akt 受乙醇调节，这些分子的调节差异可能导致 AA 和 ANA 大鼠饮酒模式的显著不同。
