Figure 6.

The increase in dopamine trails that of tyrosine hydroxylase which, like long-lived primates exhibits an overshoot before decreasing to adult levels. (A) Tyrosine hydroxylase (TH), a key enzyme involved in synthesizing monoamine neurotransmitters, levels were measured by capillary electrophoresis (CE) immunoblotting. (B) Statistical analyses on densitometric normalized values indicate a significance increase at 2–4 months of age (p = 0.0429). Levels do not significantly change between 4 months and 3 years. (C) ELISA measures of brain homogenate dopamine indicate an increase in levels through 2 years of age then a decrease at 3 years of age.