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. 2006 Feb 21;103(9):3399–3404. doi: 10.1073/pnas.0511244103

Fig. 3.

Fig. 3.

Chronic cocaine-induced increases in spine density in Drd1-EGFP- or Drd2-EGFP-positive MSNs in NAcc. (a and b) Drd1-EGFP (a) or Drd2-EGFP (b) mice were treated with saline (Sal) or cocaine (Coc, 30 mg/kg) for 4 weeks. Mouse brains 2WD or 30WD were processed for DiI labeling and immunohistochemistry as shown in Fig. 2. All spine-like protrusions on distal dendrites were included in the analysis. Data are expressed as the number of spines per 10 μm of dendritic length (mean ± SEM); ∗∗∗, P < 0.001 versus saline treated group, Kolmogorov–Smirnov test. (c and d) Cumulative frequency plots showing the distribution of spine density from individual neurons that were analyzed in a and b. One to two dendrites from one neuron in 10–15 animals per group were analyzed. The total numbers of dendrites analyzed were as follows. For D1: saline, 49 (2WD) and 38 (30WD); cocaine, 74 (2WD) and 75 (30WD). For D2: saline, 50 (2WD) and 43 (30WD); cocaine, 79 (2WD) and 89 (30WD).