SLC6A3 and nutritional disorder: Some studies have reported that nutritional iron deficiency alters dopaminergic neurotransmission, increasing the concentration of extracellular dopamine and reducing the activity of dopamine transporters and D2 receptors in the striatum [50], an essential integrative node in the dopamine transmission pathway, and striatal dopaminergic dysfunction has been linked to cortical dopaminergic dysregulation [51].