Skip to main content
. 2010 Oct 7;4:136. doi: 10.3389/fnana.2010.00136

Figure 1.

Figure 1

Summary of major differences between D1R-MSNs and D2R-MSNs based on data from BAC transgenic mice. Electrophysiological properties: D1R-MSNs appear less excitable than D2R-MSNs probably due to the different number of primary dendrites and/or differences in presynaptic input (Kreitzer and Malenka, 2007; Cepeda et al., 2008; Gertler et al., 2008). D2R-MSNs show stronger GABAA receptor-mediated synaptic responses and tonic currents than D1R-MSNs (Ade et al., 2008; Taverna et al., 2008; Janssen et al., 2009). Single back-propagating action potentials invade more distal dendritic regions in D2R- than in D1R-MSNs, a difference involving voltage-dependent Na+ channels and Kv4 K+ channels (Day et al., 2008). Corticostriatal synapses: High-frequency stimulation-induced CB1R-mediated LTD is exclusively observed in D2R-MSNs and requires stimulation of D2Rs (Kreitzer and Malenka, 2007). D2R present in cholinergic interneurons also appear important for LTD in both D1R- and D2R-MSNs, involving M1R and mGluR1 receptors (Wang et al., 2006). NMDAR-induced LTP is increased by D1R in D1R-MSNs and by A2A-R in D2R-MSNs (Shen et al., 2008). Axonal projections: extrastriatal projections of D2R-MSNs are mainly detected in the LGP, whereas D1R-MSNs provide fibers to the SNr, MGP, and, possibly, some to the LGP (Gong et al., 2003; Bertran-Gonzalez et al., 2008; Matamales et al., 2009). Unidirectional intrastriatal projections (D1R–D1R and D2R–D2R) are the most common, and D2R–D1R collaterals are more abundant than D1R–D2R (Taverna et al., 2008). Intracellular signaling: see BAC Transgenic Mice Facilitate the Identification of Distinct Populations of MSNs in the text. 6-OHDA, 6-hydroxydopamine; A2aR, adenosine 2a receptor; APBP, action potential back propagation; D1R, D1-receptor; D2R, D2-receptor; CB1R, type 1 cannabinoid receptor; LGP, lateral globus pallidus; LTD, long-term depression; LTP, long-term potentiation; M1R, muscarinic acetylcholine receptor 1; mGluR1, metabotropic glutamate receptor 1; MGP, medial globus pallidus; SNr, substantia nigra pars reticulata.