The antidepressant-sensitive dopamine transporter in Drosophila melanogaster: a primordial carrier for catecholamines.
The antidepressant-sensitive dopamine transporter in Drosophila melanogaster: a primordial carrier for catecholamines.
复制标题
DOI：
10.1124/mol.59.1.83
复制
发表时间：
2001
影响因子：
3.6
通讯作者：
Peter Pörzgen;Sang Ki Park;J. Hirsh;M. Sonders;Susan G. Amara
中科院分区：
文献类型：
--
作者：
Peter Pörzgen;Sang Ki Park;J. Hirsh;M. Sonders;Susan G. Amara
细胞外单胺类神经递质的浓度受一系列高亲和力转运蛋白的调节，这些转运蛋白是可卡因、苯丙胺和治疗抗抑郁药等精神活性药物的分子靶点。在果蝇中，可卡因诱导的行为与脊椎动物模型中的行为有惊人的相似之处。尽管果蝇中存在可卡因敏感的5-羟色胺载体，但还没有药理学或分子证据支持其他生物活性单胺存在不同的载体亚型。在这里，我们报道了可卡因敏感的苍蝇多巴胺转运蛋白(DDAT)的克隆和特性。原位杂交表明，dDAT mRNA的表达仅限于果蝇神经系统中的多巴胺能细胞。DDAT的底物选择性与哺乳动物DAT类似，因为多巴胺和酪胺是首选底物，而章鱼的转运效率较低，5-羟色胺根本不是。相比之下，dDAT抑制剂显示出与哺乳动物去甲肾上腺素转运体最相似的效力等级顺序。可卡因对克隆的dDAT具有中等高的亲和力(IC50=2.6微米)。对非洲爪哇卵母细胞中表达的dDAT的电压钳分析表明，dDAT介导的摄取是电摄取的；然而，dDAT似乎缺乏哺乳动物儿茶酚胺转运体所特有的结构性泄漏电导。DAT样底物选择性和去甲肾上腺素转运体样抑制剂药理的结合，以及系统发育分析的结果，表明dDAT代表祖先的儿茶酚胺转运体基因。鉴定出与黑腹果蝇多巴胺能神经传递相关的可卡因敏感靶点，将为进一步剖析精神刺激剂介导的行为的遗传成分奠定基础。
Extracellular concentrations of monoamine neurotransmitters are regulated by a family of high-affinity transporters that are the molecular targets for such psychoactive drugs as cocaine, amphetamines, and therapeutic antidepressants. In Drosophila melanogaster, cocaine-induced behaviors show striking similarities to those induced in vertebrate animal models. Although a cocaine-sensitive serotonin carrier exists in flies, there has been no pharmacological or molecular evidence to support the presence of distinct carrier subtypes for other bioactive monoamines. Here we report the cloning and characterization of a cocaine-sensitive fly dopamine transporter (dDAT). In situ hybridization demonstrates that dDAT mRNA expression is restricted to dopaminergic cells in the fly nervous system. The substrate selectivity of dDAT parallels that of the mammalian DATs in that dopamine and tyramine are the preferred substrates, whereas octopamine is transported less efficiently, and serotonin not at all. In contrast, dDAT inhibitors display a rank order of potency most closely resembling that of mammalian norepinephrine transporters. Cocaine has a moderately high affinity to the cloned dDAT (IC50 = 2.6 microM). Voltage-clamp analysis of dDAT expressed in Xenopus laevis oocytes indicates that dDAT-mediated uptake is electrogenic; however, dDAT seems to lack the constitutive leak conductance that is characteristic of the mammalian catecholamine transporters. The combination of a DAT-like substrate selectivity and norepinephrine transporter-like inhibitor pharmacology within a single carrier, and results from phylogenetic analyses, suggest that dDAT represents an ancestral catecholamine transporter gene. The identification of a cocaine-sensitive target linked to dopaminergic neurotransmission in D. melanogaster will serve as a basis for further dissection of the genetic components of psychostimulant-mediated behavior.