Platelet alpha 2-adrenergic receptor binding and the effects of d-amphetamine in boys with attention deficit hyperactivity disorder.
Presynaptic inhibitory alpha-adrenergic receptors are involved in regulating the release of norepinephrine (NE) through a negative feedback mechanism mediated by NE. Increased alpha2-adrenergic receptor activity suggests decrease NE release and activity, while decreased alpha2-adrenergic activity suggests increase NE release and activity. A large body of evidence suggests the involvement of a disturbance in NE activity in the pathophysiology of attention deficit hyperactivity disorder (ADHD) in childhood. Platelet alpha2-adrenergic receptor binding was compared in 23 boys aged 7-12 with the diagnosis of ADHD and 11 normal controls. The ADHD boys tended to have lower levels of alpha2-binding than controls. The administration of d-amphetamine in a double-blind placebo-controlled crossover design did not have any effect on alpha2-receptor binding in ADHD boys. Nonresponders to d-amphetamine had the lowest alpha2-receptor binding compared to responders and controls. These findings suggest a normal alpha2-adrenergic activity in ADHD boys responders to d-amphetamine and a possible increase in NE release in ADHD boys nonresponders to d-amphetamine due to decreased alpha2-adrenergic receptors.
Division of Mental Retardation and Child Psychiatry, UCLA Neuropsychiatric Institute.
W O
WO
Shekim
D B
DB
Bylund
K
K
Hodges
R
R
Glaser
C
C
Ray-Prenger
G
G
Oetting
D001289:Attention Deficit Disorder with Hyperactivity / Q000097:blood / Q000188:drug therapy*; D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism; D002648:Child; D003913:Dextroamphetamine / Q000009:adverse effects / Q000627:therapeutic use*; D004311:Double-Blind Method; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009433:Neural Inhibition / Q000187:drug effects / Q000502:physiology; D009638:Norepinephrine / Q000097:blood*; D018341:Receptors, Adrenergic, alpha-2 / Q000187:drug effects* / Q000502:physiology; D015016:Yohimbine / Q000493:pharmacokinetics
D018341:Receptors, Adrenergic, alpha-2; D015016:Yohimbine; D003913:Dextroamphetamine; D009638:Norepinephrine