Evaluation of D1 and D2 dopamine receptor segregation in the developing striatum using BAC transgenic mice

• Published in: PloS one 2013-07, Vol.8 (7), p.e67219-e67219
• Main Authors: Thibault, Dominic, Loustalot, Fabien, Fortin, Guillaume M, Bourque, Marie-Josée, Trudeau, Louis-Éric
• Format: Article
• Language: English
• Subjects: Animal models; Animals; Artificial chromosomes; Axons; Bacteria; Bacterial artificial chromosomes; Biology; Brain research; Chromosomes, Artificial, Bacterial; Corpus Striatum - cytology; Corpus Striatum - embryology; Corpus Striatum - metabolism; Dopamine; Dopamine - metabolism; Dopamine D1 receptors; Dopamine D2 receptors; Dopamine receptors; Embryo, Mammalian; Experiments; Gene expression; Gene Expression Regulation, Developmental; Genes, Reporter; Green Fluorescent Proteins - genetics; Green Fluorescent Proteins - metabolism; Kinases; Medicine; Mice; Mice, Transgenic; Neostriatum; Neurons; Neurons - cytology; Neurons - metabolism; Neurosciences; Ontogeny; Organ Specificity; Pathways; Pharmacology; Primary Cell Culture; Receptors; Receptors, Dopamine D1 - genetics; Receptors, Dopamine D1 - metabolism; Receptors, Dopamine D2 - genetics; Receptors, Dopamine D2 - metabolism; Rodents; Segregation process; Spiny neurons; Striatum; Transgenic animals; Transgenic mice
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0067219

The striatum is predominantly composed of medium spiny neurons (MSNs) that send their axons along two parallel pathways known as the direct and indirect pathways. MSNs from the direct pathway express high levels of D1 dopamine receptors, while MSNs from the indirect pathway express high levels of D2 dopamine receptors. There has been much debate over the extent of colocalization of these two major dopamine receptors in MSNs of adult animals. In addition, the ontogeny of the segregation process has never been investigated. In this paper, we crossed bacterial artificial chromosome drd1a-tdTomato and drd2-GFP reporter transgenic mice to characterize these models and estimate D1-D2 co-expression in the developing striatum as well as in striatal primary cultures. We show that segregation is already extensive at E18 and that the degree of co-expression further decreases at P0 and P14. Finally, we also demonstrate that cultured MSNs maintain their very high degree of D1-D2 reporter protein segregation, thus validating them as a relevant in vitro model.