Swarzenski B C, Tang L, Oh Y J, O'Malley K L, Todd R D
Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110.
Proc Natl Acad Sci U S A. 1994 Jan 18;91(2):649-53. doi: 10.1073/pnas.91.2.649.
Molecular cloning studies have defined a family of dopamine D2-like receptors (D2, D3, and D4), which are the products of separate genes. Our previous work has shown that stimulation of dopamine D2-like receptors in cultures of fetal cortical neurons increases the extension and branching of neurites. To determine which D2-like receptors possess morphogenic potentials, a clonal mesencephalic cell line (MN9D) was transfected with D2, D3, or D4 receptor subtypes and treated with quinpirole, an agonist of D2-like receptors, and changes in morphological characteristics were quantitated. Stimulation of D2 receptors increased the number and branching of neurites with little effect on neurite extension; stimulation of D3 and D4 receptors increased the branching and extension of neurites. Similar results were found for primary mesencephalic cultures stimulated with quinpirole. These results suggest that the known D2-like receptors have specific developmental roles in regulating neuronal morphogenesis of dopaminergic pathways.
分子克隆研究已经确定了一个多巴胺D2样受体家族（D2、D3和D4），它们是不同基因的产物。我们之前的研究表明，在胎儿皮质神经元培养物中刺激多巴胺D2样受体可增加神经突的延伸和分支。为了确定哪些D2样受体具有形态发生潜能，将克隆的中脑细胞系（MN9D）用D2、D3或D4受体亚型转染，并用D2样受体激动剂喹吡罗处理，对形态学特征的变化进行定量分析。刺激D2受体增加了神经突的数量和分支，对神经突延伸影响很小；刺激D3和D4受体增加了神经突的分支和延伸。在用喹吡罗刺激的原代中脑培养物中也发现了类似的结果。这些结果表明，已知的D2样受体在调节多巴胺能通路的神经元形态发生中具有特定的发育作用。
