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Dopamine system
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COMT (Val158Met)
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Catechol-o-methyltransferase
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Degradation of catecholamines
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Met variant- carriers have reduced COMT activity
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Prefrontal Cortex
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Differential dopaminergic signaling influences PFC function (COMT-genotype model), may explain different drug effects [58]
|
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DRD4 (exon 3 VNTR)
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Dopamine receptor D4
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Dopaminergic transmission
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7R-carriers have reduced DRD4 function
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Prefrontal Cortex
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Variation in dopaminergic signaling influences PFC function, interaction with other genotypes [25]
|
|
SLC6A3 (3′UTR VNTR); SLC6A3 (3′UTR VNTR/intron 8 VNTR haplotype)
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Dopamine transporter
|
Reuptake of dopamine
|
9R- vs. 10R-carriers have reduced or increased DAT availability (inconsistent findings)
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Striatum
|
Variability of striatal dopamine Transporter availability influences PFC function directly or indirectly via cortico-striatal pathways [24]
|
|
Serotonin system
| | | | | |
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TPH2 (e.g. rs4570625, rs11178997)
|
Tryptophan hydroxylase 2
|
Synthesis of serotonin
|
Influences transcriptional activity
|
Raphe nuclei, with ubiquitous action of serotonin
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Differential activity of the cortico-limbic circuit
|
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Others
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NOS1 exon 1f-VNTR
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Neuronal nitric oxide (NO) synthase
|
Synthesis of neuronal NO
|
Allelic variation in reporter gene expression
|
Striatum
|
NO function influences dopamine signaling [32]
|
|
LPHN3 (ADHD risk haplotype)
|
Latrophilin
|
Adhesion G-protein coupled receptor (?)
|
Decreased NAA/Cr ratio in risk haplotype carriers
|
Amygdala, caudate nucleus, cerebellum, and cerebral cortex
|
Possibly influences dopamine-glutamatergic system interaction
|
