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. 2012 Jan 5;7(1):e29867. doi: 10.1371/journal.pone.0029867

Figure 4. Relationship of dopamine tissue content to tyrosine hydroxylase protein and phosphorylation in vivo.

Figure 4

DA tissue content and its relationship to recovered TH protein and phosphorylation shows differences in terminal field and somatodendritic TH activity in the four DA regions (n = 20 for all regions except SN (19)) in BNF rats. Values for pmols DA per mg protein were striatum = 842±34, SN = 39±2, NAc = 472±18, and VTA = 125±8. Values for ng TH per mg protein were striatum = 343±16, SN = 96±5, NAc = 256±16, and VTA = 179±16. A. pmols DA per ng TH protein in dissected DA neuropil. DA per TH was calculated by dividing the pmols DA per mg protein by the ng TH per mg protein for each sample. DA per TH was significantly greater in terminal field regions compared to somatodendritic regions. Repeated measures ANOVA, p<0.0001,F = 60.2, post-hoc: (***str vs. SN, t = 11.6, p<0.001; str vs. NAc, t = 2.74, ns; ***str vs. VTA, t = 9.57, p<0.001; ***SN vs. NAc, t = 8.83, p<0.001; SN vs. VTA, t = 2.00, ns; ***NAc v. VTA, t = 6.83, p<0.001). The pmols DA per ng TH values were str = 2.52±0.12, SN = 0.42±0.02, NAc = 2.02±0.20, VTA = 0.78±0.07. B. ser31 phosphorylation stoichiometry. TH phosphorylation stoichiometry at ser31 was significantly higher in the striatum than all other regions while ser31 phosphorylation stoichiometry was significantly higher in terminal field regions compared to somatodendritic regions (ANOVA, p<0.0001, F = 53.1, post-hoc (***str v. SN, t = 11.7, p<0.001; ***str v. NAc, t = 5.80, p<0.001; ***str v. VTA, t = 9.75; p<0.001; ***SN v. NAc, t = 5.87, p<0.001; ***NAc v. VTA, t = 3.95, p<0.001)). Stoichiometry values were str = 0.290±0.017, SN = 0.069±0.007, NAc = 0.183±0.019, VTA = 0.104±0.007. These differences reflect the differences in DA per TH observed in Fig 4A . C. ser40 phosphorylation stoichiometry. TH phosphorylation stoichiometry at ser40 was significantly different between all brain regions except between the striatum and the SN with ser40 phosphorylation being greater in the mesoaccumbens pathway than the nigrostriatal pathway (ANOVA, p<0.0001, F = 31.8, post-hoc (***str v. NAc, t = 7.52, p<0.001; **Str v. VTA, t = 3.89, p<0.01, ***SN v. NAc, t = 8.81, p<0.001; ***SN v. VTA, t = 5.19, p<0.001; **NAc v. VTA, t = 3.62, p<0.01). Stoichiometry values were str = 0.025±0.002, SN = 0.016±0.002, NAc = 0.070±0.006, VTA = 0.051±0.004.