Cass W A, Gerhardt G A
Department of Anatomy and Neurobiology, University of Kentucky, Lexington 40536-0084, USA.
J Neurochem. 1995 Jul;65(1):201-7. doi: 10.1046/j.1471-4159.1995.65010201.x.
In vivo electrochemistry was used to characterize dopamine clearance in the medial prefrontal cortex and to compare it with clearance in the dorsal striatum and nucleus accumbens. When calibrated amounts of dopamine were pressure-ejected into the cortex from micropipettes adjacent to the recording electrodes, transient and reproducible dopamine signals were detected. The local application of the selective uptake inhibitors GBR-12909, desipramine, and fluoxetine before the application of dopamine indicated that at the lower recording depths examined (2.5-5.0 mm below the brain surface), locally applied dopamine was cleared from the extracellular space primarily by the dopamine transporter. The norepinephrine transporter played a greater role at the more superficial recording sites (0.5-2.25 mm below the brain surface). To compare clearance of dopamine in the medial prefrontal cortex (deeper sites only), striatum, and nucleus accumbens, varying amounts of dopamine were locally applied in all three regions of individual animals. The signals recorded from the cortex were of greater amplitude and longer time course than those recorded from the striatum or accumbens (per picomole of dopamine applied), indicating less efficient dopamine uptake in the medial prefrontal cortex. The fewer number of transporters in the medial prefrontal cortex may be responsible, in part, for this difference, although other factors may also be involved. These results are consistent with the hypothesis that regulation of dopaminergic function is unique in the medial prefrontal cortex.
采用体内电化学方法来表征内侧前额叶皮质中多巴胺的清除情况，并将其与背侧纹状体和伏隔核中的清除情况进行比较。当将校准量的多巴胺从与记录电极相邻的微量移液器压力喷射到皮质中时，可检测到瞬态且可重复的多巴胺信号。在施加多巴胺之前局部应用选择性摄取抑制剂GBR - 12909、地昔帕明和氟西汀表明，在所检查的较低记录深度（脑表面以下2.5 - 5.0毫米），局部应用的多巴胺主要通过多巴胺转运体从细胞外空间清除。去甲肾上腺素转运体在较浅的记录部位（脑表面以下0.5 - 2.25毫米）发挥更大作用。为了比较内侧前额叶皮质（仅较深部位）、纹状体和伏隔核中多巴胺的清除情况，在个体动物的所有三个区域局部应用不同量的多巴胺。从皮质记录到的信号比从纹状体或伏隔核记录到的信号（每皮摩尔应用的多巴胺）幅度更大、时程更长，表明内侧前额叶皮质中多巴胺摄取效率较低。内侧前额叶皮质中转运体数量较少可能部分导致了这种差异，尽管也可能涉及其他因素。这些结果与多巴胺能功能调节在内侧前额叶皮质中具有独特性这一假设一致。
