Simon J R, Ghetti B
Department of Psychiatry, Indiana University School of Medicine, Indianapolis 46202-4887.
Neurochem Int. 1993 May;22(5):471-7. doi: 10.1016/0197-0186(93)90042-4.
Slices of the substantia nigra from normal mice and from mice with the weaver gene were used to study somatodendritic uptake of dopamine. The substantia nigra of the homozygous weaver mouse is deficient in both cell bodies and dendrites whereas the substantia nigra of the heterozygous weaver mouse is deficient only in dendrites. Accumulation of [3H]dopamine by nigral slices obtained from each genotype was not different from that observed in slices obtained from control mice. The observed accumulation of [3H]dopamine was apparently taking place predominantly into serotonergic and noradrenergic elements since significant reductions were obtained by both fluoxetine and desipramine at concentrations that were selective for the serotonin and norepinephrine carriers, respectively. In the absence, as well as in the presence of fluoxetine and desipramine, dopamine accumulation in the substantia nigra was only slightly attenuated by the known dopamine uptake blocker GBR 12909. These data argue against a significant presence of somatodendritic uptake systems for dopamine in the substantia nigra and suggest that caution be used in the interpretation of results from studies on dopamine release from nigral slices when [3H]dopamine has been used to preload the tissue. Under such experimental conditions, it is likely that a large proportion of the released tritium might come from neurons other than those which contain endogenous neurotransmitter dopamine.
使用来自正常小鼠和携带韦弗基因小鼠的黑质切片来研究多巴胺的树突体摄取。纯合韦弗小鼠的黑质在细胞体和树突方面均有缺陷，而异合子韦弗小鼠的黑质仅在树突方面有缺陷。从每种基因型获得的黑质切片对[3H]多巴胺的积累与从对照小鼠获得的切片中观察到的情况没有差异。观察到的[3H]多巴胺积累显然主要发生在血清素能和去甲肾上腺素能元件中，因为分别对血清素和去甲肾上腺素载体具有选择性的氟西汀和地昔帕明在一定浓度下都能使积累显著减少。在不存在以及存在氟西汀和地昔帕明的情况下，已知的多巴胺摄取阻滞剂GBR 12909仅略微减弱黑质中多巴胺的积累。这些数据表明黑质中不存在大量的多巴胺树突体摄取系统，并建议在解释使用[3H]多巴胺预加载组织时黑质切片多巴胺释放研究结果时要谨慎。在这种实验条件下，释放的大量氚可能来自含有内源性神经递质多巴胺以外的神经元。
