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Parallel loss of presynaptic and postsynaptic dopamine markers in normal aging
N D Volkow1, G J Wang, J S Fowler
1Medical Department, Brookhaven National Laboratory, Upton, NY 11973, USA.
Annals of Neurology
|July 17, 1998
Summary
Brain aging involves dopamine decline, but not from cell loss. Positron emission tomography shows age-related dopamine transporter and D2 receptor losses are linked, suggesting a shared regulatory mechanism independent of age.
Area of Science:
- Neuroscience
- Gerontology
- Neurochemistry
Background:
- Human brain aging is linked to decreased dopamine (DA) function.
- This decline is often attributed to the loss of DA-producing cells.
Purpose of the Study:
- To investigate the relationship between age-related changes in dopamine transporters and D2 receptors.
- To determine if these changes are associated with DA cell loss or striatal metabolism.
Main Methods:
- Utilized positron emission tomography (PET) in healthy individuals.
- Examined correlations between presynaptic (DA transporters) and postsynaptic (D2 receptors) markers.
- Assessed the relationship with striatal metabolism and age.
Main Results:
- Age-related losses in DA transporters were associated with losses in D2 receptors.
- This association was not observed with increases, as seen in DA cell loss.
- The correlation was specific to DA synaptic markers and not linked to striatal metabolism.
- The association between transporter and receptor loss was independent of age.
Conclusions:
- Age-related dopamine transporter and D2 receptor losses are linked in healthy aging.
- This suggests a common regulatory mechanism for these synaptic markers, irrespective of age.
- The findings challenge the interpretation of dopamine decline solely as DA cell loss.