Dopamintransporter - Struktur, Funktion und Bedeutung für die ADHS

Der Dopamintransporter (DAT) sorgt für den Rücktransport von Dopamin aus dem synaptischen Spalt in das präsynaptische Neuron und hat somit eine Schlüsselrolle für die neuronale Dopaminaktivität. Auffälligkeiten am DAT1-Gen sind bei ADHS beschrieben. Bei unbehandelten Patienten mit ADHS wurden meist erhöhte DAT-Verfügbarkeiten im SPECT festgestellt, die durch Methylphenidat (MPH) korrigiert werden können; finden sich primär keine erhöhten Werte für die DAT-Verfügbarkeit, wirkt MPH kaum oder gar nicht. Wichtige Beziehungen bestehen zwischen DAT und Zinkstoffwechsel, Nikotinabusus, Alkoholkonsum sowie Halluzinationen bei psychotischen Patienten. Neuroleptika beeinflussen den Dopaminstoffwechsel durch die Blockade der postsynaptischen Rezeptoren im Vergleich zu Stimulanzien antagonistisch; dies wäre eine Erklärung für die klinisch häufig zu beobachtende vermehrte Akathisie bei Patienten mit ADHS im Rahmen von Narkosen mit Neuroleptika.

The dopamine transporter (DAT) mediates the reuptake of dopamine from the synaptic cleft into the presynaptic neuron and has a key role for the neuronal dopamine activity. Involvement of a polymorphism of the DAT1 gene in ADHD has been described. In untreated patients with ADHD high DAT availability in SPECT has been found in most cases, which can be corrected by methylphenidate (MPH); patients with low DAT availability seem not to respond to MPH. Important relations exist between DAT and zinc, nicotine, alcohol as well as halluzinations in psychotic patients. Neuroleptics influence dopamine metabolism by blocking the postsynaptic receptors in an antagonistic matter compared to stimulants ; this could be an explanation for the frequently observed akathisia in patients with ADHD after anesthesia with neuroleptics.

Key Words

dopamine transporter (DAT) - attention deficit/hyperactivity disorder (ADHD) - zinc - nicotine - DAT1 gene - SPECT

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