Department of Chemistry and R. N. Adams Institute of Bioanalytical Chemistry, University of Kansas, Lawrence, KS 66045, USA.
Neuroscience. 2011 Mar 17;177:223-9. doi: 10.1016/j.neuroscience.2011.01.001. Epub 2011 Jan 8.
Methionine sulfoxide reductase A knockout (MsrA-/-) mice, which serve as a potential model for neurodegeneration, suffer from increased oxidative stress and have previously been found to have chronically elevated brain dopamine (DA) content levels relative to control mice. Additionally, these high levels parallel the increased presynaptic DA release. In this study, fast-scan cyclic voltammetry (FSCV) at carbon-fiber microelectrodes was used to quantify striatal reserve pool DA in knockout mice and wild-type control mice. Reserve pool DA efflux, induced by amphetamine (AMPH), was measured in brain slices from knockout and wild type (WT) mice in the presence of α-methyl-p-tyrosine, a DA synthesis inhibitor. Additionally, the stimulated release of reserve pool DA, mobilized by cocaine (COC), was measured. Both efflux and stimulated release measurements were enhanced in slices from knockout mice, suggesting that these mice have greater reserve pool DA stores than wild-type and that these stores are effectively mobilized. Moreover, dopamine transporter (DAT) labeling data indicate that the difference in measured DA efflux was likely not caused by altered DAT protein expression. Additionally, slices from MsrA-/- and wild-type mice were equally responsive to increasing extracellular calcium concentrations, suggesting that potential differences in either calcium entry or intracellular calcium handling are not responsible for increased reserve pool DA release. Collectively, these results demonstrate that MsrA-/- knockout mice maintain a larger DA reserve pool than wild-type control mice, and that this pool is readily mobilized.
蛋氨酸亚砜还原酶 A 敲除(MsrA-/-)小鼠可作为神经退行性变的潜在模型,其氧化应激增加,并且先前发现其脑多巴胺(DA)含量水平相对于对照小鼠慢性升高。此外,这些高水平与增加的突触前 DA 释放平行。在这项研究中,使用碳纤维微电极的快速扫描循环伏安法(FSCV)来量化敲除小鼠和野生型对照小鼠纹状体储备池 DA。在 DA 合成抑制剂α-甲基-对酪氨酸存在的情况下,在敲除和野生型(WT)小鼠的脑切片中测量由安非他命(AMPH)诱导的储备池 DA 外排。此外,还测量了由可卡因(COC)动员的储备池 DA 的刺激释放。敲除小鼠的外排和刺激释放测量均增强,表明这些小鼠具有比野生型更大的储备池 DA 储存,并且这些储存可以有效动员。此外,多巴胺转运蛋白(DAT)标记数据表明,测量的 DA 外排差异可能不是由 DAT 蛋白表达改变引起的。此外,MsrA-/-和野生型小鼠的切片对增加的细胞外钙浓度同样敏感,表明钙内流或细胞内钙处理的潜在差异不是增加储备池 DA 释放的原因。总之,这些结果表明,MsrA-/-敲除小鼠比野生型对照小鼠维持更大的 DA 储备池,并且该池容易动员。