帕罗西汀对应激抑郁模型大鼠脑区蛋白激酶PKA、PKC和CaMKII活力的影响

目的 探讨帕罗西汀对应激抑郁模型大鼠脑区蛋白激酶PKA、PKC和CaMKII活力的影响.方法 将成年雄性SD大鼠随机分为6组:对照组(Ⅰ)、抑郁模型组(Ⅱ)、抑郁模型 给药1次组(Ⅲ)、抑郁模型 给药1周组(Ⅳ)、抑郁模型 给药2周组(Ⅴ)和抑郁模型 给药4周组(Ⅵ).抑郁模型为强迫大鼠游泳4周.采用同位素法检测蛋白激酶PKA、PKC和CaMKII的活力.结果 (1)在海马,Ⅱ、Ⅲ、Ⅳ、及Ⅴ组大鼠PKA分别为(3.92±0,23)×10-2,(3.68±0.092)×10-2,(3.56±0.1)×10-2,和(3.52±0.18)×10-2]和CaMKII分别为(12.89±0.31)×10-2,(15.08±2.07)×10-2,(16.32±2.87)×10-2,和(17.00±1.52)×10-2]活力明显低于Ⅰ组PKA(5.63±0.41)×10-2;CaMKII(48.91±1.86)×10-2]和Ⅵ组PKA(4.92±0.36)×10-2;CaMKII(46.74±1.34)×10-2(P<0.01或P<0.05);Ⅱ组大鼠PKC的活力(0.55±0.017)×10-2]明显低于对照组(1.48±0.27)×10-2](P<0.01),各用药组大鼠海马PKC活力与对照组比较差异无统计学意义(P>0.05)(2)在前额叶皮质,Ⅱ、Ⅲ,Ⅳ组大鼠PKA活力分别为(0.9±0.027)×10-2,(0.92±0.081)×10-2,(0.92±0.028)×10-2]与对照组(0.99±0.072)×10-2]比较差异无统计学意义(P>0.05);而V(1.14±0.045)×10-2和Ⅵ(1.27±0.040)×10-2组的PKA活性则显著高于其它四组(P<0.01);Ⅱ和Ⅲ组的PKC活性分别为(0.15±0.013)×10-2,(0.14±0.007)×10-2)]均显著高于对照组(0.099±0.0007)×10-2]和其它用药组(P<0.01),Ⅳ组PKC活性(0.1±0.0006)x10-2]与Ⅰ组比较差异无统计学意义(P>0.05),Ⅴ和Ⅵ组PKC活性分别为(0.077±0.0005)×10-2,(0.03±0.00017)×10-2]显著低于Ⅰ组(P<0.01);模型组(6.84±0.22)×10-2]和各用药组分别为(6.68±0.23)×10-2,(6.89±0.15)×10-2,(6.55±0.14)×10-2,(6.53±0.13)×10-2]的CaMKII活性显著低于埘照组(16.57±0.19)×10-2](P<0.01).结论 帕罗西汀长期用药逆转慢性应激所致大鼠海鸟PKA、PKC和CaMKII活力降低,而对前额叶皮质PKA、PKC和CaMKII活力改变的作用复杂.

Effects of paroxetine on protein kinase PKA, PKC and CaMKII activity in different brain regions in a rat depression model

OBJECTIVE: To evaluate the effects of paroxetine on protein kinase PKA, PKC and CaMKII activities in different brain regions in a rat model of depression. METHODS: Thirty-six adult male SD rats were randomized into 6 groups, including one control group (I) and 5 groups of depression model established by forcing the rats to swim for 4 weeks. The 5 depression groups received no treatment (II) or were treated with paroxetine at a single dose (III), for a week (IV), 2 weeks (V) or 4 weeks (VI). The radioactivity of PKA, PKC and CaMKII in the hippocampus and prefrontal cortex was quantitatively measured using a liquid scintillation counter. RESULTS: In the rat hippocampus, PKA and CaMKII activities were significantly lower in groups II, III, IV, and V than in groups I and VI (P<0.01 or P<0.05), but comparable between groups VI and I (P>0.05). PKC activity was significantly lower in group II than in group I (P<0.01), but showed no significant difference between the paroxetine-treated groups and group I (P>0.05). In the prefrontal cortex, the activity of PKA in groups I, II, III, and IV was similar (P>0.05), but all significantly lower than that in groups V and VI (P<0.01). PKC activity was significantly higher in groups II and III than that in group I and other paroxetine-treated groups (P<0.01), and similar between groups IV and I (P>0.05); groups V and VI had significantly lower PKC activity than group I (P<0.01). Group I had the highest CaMKII activity among the groups (P<0.01). CONCLUSION: Chronic administration of paroxetine can reverse chronic stress-induced inhibition of PKA, PKC and CaMKII activity in rat hippocampus, while the effects of paroxetine on the protein kinases can be more complex in prefrontal cortex.