Article Figures & Data
Figures
- Figure 1.
Progressive DA cell loss in the ventral midbrain of En1+/− mice. A, TH-positive cells in the ventral midbrain of WT and En1+/− mice at 3 and 48 weeks postnatal. B, Progressive loss of DA neurons in SN with age in En1+/− mice (3, 8, 16, 24, 48 weeks postnatal). En1+/− versus WT, **p < 0.01 and ***p < 0.001 (3 vs 8 weeks, #p < 0.05; vs 16 weeks, ##p < 0.01; vs 24 and 48 weeks, ###p < 0.001). Actual numbers from which percentages of surviving neurons were calculated at each age are provided in supplemental Table 1 (available at www.jneurosci.org as supplemental material). C, Loss of DA neurons in VTA of En1+/− mice (3 and 48 weeks postnatal). For 48 versus 3 weeks, #p < 0.05; En1+/− versus WT, **p < 0.01 (n = 3–4 by group of age and genotype).
- Figure 2.
Neuronal cells in SN. A, Middle section of the SN (mid-SN) stained for TH. The surface of the SN is outlined by the dashed line. B, Measuring mid-SN surfaces indicates that En1+/− (n = 3) and WT (n = 3) mice show no differences in SN size at 3 and 24 weeks of age. C, TH (red) and NeuN (green) staining of SN cells. Shown are examples of non-DA neurons (arrows) and of DA neurons (arrowheads; yellow; merged picture). D, Decrease of total neuron number in En1+/− versus WT mice between 3 and 48 weeks of age (48 vs 3 weeks, ##p < 0.01; En1+/− vs WT, ***p < 0.001; n = 3–4 by group of age and genotype). Actual numbers from which percentages of surviving neurons were calculated are provided in supplemental Table 1 (available at www.jneurosci.org as supplemental material). E, Striatal DA contents in WT (n = 8) and En1+/− (n = 10) mice at 55 weeks postnatal (**p < 0.01). F, DA turnover of WT and En1+/− mice at 55 weeks postnatal (***p < 0.001). G, Striatal serotonin (5-HT) contents in WT and En1+/− mice at 55 weeks postnatal (NS).
- Figure 3.
Gain of function by intraparenchymal infusion of En2 protein. A, After 14 d of infusion, En2 is detected in a large amount in a region encompassing the SN. Anterior sections are to the left and posterior to the right. B, Progressive loss of DA neurons in SN of En1+/− mice compared with WT expressed as the mean ± SD. At 3 weeks postnatal, the WT and En1+/− mice possess the same number of TH-positive cells in the SN. A decrease of ∼20% is observed at 8 weeks postnatal and of ∼28% at 16 weeks. Between 6 and 9 weeks postnatal, the En1+/− mice lose ∼10% of DA cells. C, Rescue of DA cell loss in En1+/− mice by En2 infusion above the SN. At 9 weeks postnatal, the control En1+/− mice have lost ∼20% of DA cells as compared with the WT (***p < 0.001). No significant difference in TH-positive cell numbers is found between WT infused with saline or WT infused with En2 (p = 0.4; NS). Infusion of En2 in En1+/− mice prevents cell loss in the SN. At 9 weeks postnatal, after 2 weeks of En2 infusion, the number of TH-positive neurons is increased significantly by ∼15% in En1+/− mice as compared with control (**p < 0.01) and is equivalent to the number of DA cells in WT infused with saline or En2.
- Figure 4.
Locomotor activity. Performances in an open field of 24-week-old En1+/− and WT mice expressed as the mean ± SD of distance traveled in centimeters (A), number (mean ± SD) of rearings (B), and time spent in the central zone (C); **p < 0.01. D, Effect of amphetamine (2 mg/kg) on the distance traveled in the open field (in centimeters; mean ± SD) by WT and En1+/− mice during the 30 min that follow injection. Mice are 32–33 weeks old at the time of the test. Animals receive either saline (Sal) or amphetamine (Amph). Differences (Student's t test): En1+/− versus WT, *p < 0.05; Amph versus Sal, #p < 0.05 and ##p < 0.01. Amphetamine administration at a dose of 5 mg/kg induces hyperactivity in both WT and En1+/− mice (data not shown). E, Rotarod performances of 27-week-old En1+/− and WT mice expressed as the mean ± SD of latency (s) to fall (average of 3 trials). Although the same trend (decreased performance for En1+/− mice) was observed at all speeds, the difference did not reach significance because of the abnormally high performances of one mutant mouse of 10 (see Results).
- Figure 5.
Forced swimming test. Performances of 26-week-old En1+/− and WT mice in forced swimming test are expressed as the mean ± SD of immobility time during the first (A) and the second (B) test exposure; *p < 0.05 and **p < 0.01. C, Performances in an open field of 24-week-old En1+/− and WT mice tested in FST expressed as the mean ± SD of the distance traveled (in centimeters); *p < 0.05.
- Figure 6.
Saccharin consumption test. Shown is the Preference Index for saccharin (A) and total fluid intake (B) in 35-week-old En1+/− and WT mice expressed as the mean ± SD during a two-bottle free choice paradigm of saccharin consumption; *p < 0.05 and ***p < 0.001.
Additional Files
HTML Page - index.htslp
Files in this Data Supplement:
- supplemental material - Supplemental material and legends
- supplemental material - Legend to figure S1. Elevated plus maze Assessment of anxiety-like behaviors in 24 week-old En1+/- and WT mice in elevated plus maze expressed as mean � SD of percent of time and percent of entries into open arms.
