Department of Chemistry, 1251 Wescoe Hall Drive, University of Kansas , Lawrence, Kansas 66045, United States.
ACS Chem Neurosci. 2017 Sep 20;8(9):1880-1888. doi: 10.1021/acschemneuro.7b00022. Epub 2017 Jun 28.
Zebrafish (Danio rerio) have recently emerged as useful model organism for the study of neuronal function. Here, fast-scan cyclic voltammetry (FSCV) at carbon-fiber microelectrodes was used to measure locally evoked dopamine release and uptake in zebrafish whole brain preparations and results were compared with those obtained from brain slices. Evoked dopamine release ([DA]) was similar in whole brain and sagittal brain slice preparations (0.49 ± 0.13 μM in whole brain and 0.59 ± 0.28 μM in brain slices). Treatment with α-methyl-p-tyrosine methyl ester (αMPT), an inhibitor of tyrosine hydroxylase, diminished release and the electrochemical signal reappeared after subsequent drug washout. No observed change in stimulated release current occurred after treatment with desipramine or fluoxetine in the whole brain. Treatment with the uptake inhibitors, nomifensine or GBR 12909 increased [DA], while treatment with sulpiride, a D2 dopamine autoreceptor antagonist, resulted in increased stimulated dopamine release in whole brain, but had no effect on release in slices. Dopamine release in whole brains increased progressively up to an electrical stimulation frequency of 25 Hz, while release in slices increased up to a frequency of only 10 Hz and then plateaued, highlighting another key difference between these preparations. We observed a lag in peak dopamine release following stimulation, which we address using diffusion models and pharmacological treatments. Collectively, these results demonstrate the electrochemical determination of dopamine release in the whole, intact brain of a vertebrate species ex vivo and are an important step for carrying out further experiments in zebrafish.
斑马鱼（Danio rerio）最近已成为研究神经元功能的有用模式生物。在这里，使用碳纤维微电极的快速扫描循环伏安法（FSCV）来测量斑马鱼全脑制备物中局部诱发的多巴胺释放和摄取，并且将结果与从脑切片获得的结果进行比较。在全脑和矢状脑切片制备物中，诱发的多巴胺释放（[DA]）相似（全脑为 0.49 ± 0.13 μM，脑切片为 0.59 ± 0.28 μM）。用酪氨酸羟化酶抑制剂α-甲基-对-酪氨酸甲酯（αMPT）处理可减少释放，并且在随后的药物冲洗后电化学信号再次出现。在用去甲丙咪嗪或氟西汀处理全脑时，未观察到刺激释放电流发生变化。用摄取抑制剂诺米芬辛或 GBR 12909 处理会增加[DA]，而用 D2 多巴胺自受体拮抗剂舒必利处理会导致全脑中刺激的多巴胺释放增加，但对切片中的释放没有影响。全脑中的多巴胺释放逐渐增加至 25 Hz 的电刺激频率，而切片中的释放增加至仅 10 Hz 的频率，然后趋于平稳，这突出了这些制剂之间的另一个关键差异。我们观察到刺激后多巴胺释放的峰值出现滞后，我们使用扩散模型和药理学处理来解决这个问题。总之，这些结果证明了在脊椎动物物种的整个完整脑中进行电化学多巴胺释放的测定，这是在斑马鱼中进行进一步实验的重要步骤。
