Table 1. in vivo relationship of DA tissue content to TH phosphorylation.

Region comparison	pmols DA perpmol TH	ser31 ps	ser40 ps*	ser19 ps**
Str v. SN	6.13	4.20	1.56	0.18
Str v. NAc	1.25	1.58	0.46	0.50
Str v. VTA	3.20	2.78	0.49	0.10
SN v. NAc	0.20	0.38	0.30	2.78 #
SN v. VTA	0.52	0.66	0.31	0.56
NAc v. VTA	2.57	1.76	1.06	0.20

Legend: The ratio of the described values compare DA per TH and site specific TH phosphorylation stoichiometry (ps) for each possible combination of comparisons in the four DA brain regions examined. For example, in striatum the pmols DA per pmol TH value is 141 while in the SN this value is 23. Thus, the ratio comparing these values for Str v. SN is 141/23 or 6.13. There was a significant difference between the six ratios comparing DA per TH versus ser40 and versus ser19 ps, but not ser31 ps. These data are evidence that under basal conditions, ser31 phosphorylation regulates DA bioavailability within the terminal field and somatodendritic compartments in vivo. Repeated Measures ANOVA (p = 0.0092, F = 6.1) followed by Dunnett's Multiple Comparison Test (DA per TH vs ser31 ps, q = 0.82, ns; DA per TH vs. ser40 ps, q = 2.98, *p<0.05; DA per TH vs. ser19 ps, q = 3.69, **p<0.01).

^#The value for ser19 ps comparing SN v. NAc was excluded from the analysis because it was determined to be a significant outlier by the Grubbs' test (p<0.01, Z = 2.01).