Acetyl-L-carnitine reduces impulsive behaviour in adolescent rats.
The attention deficit/hyperactivity disorder (ADHD) can affect human infants and adolescents. One important feature of this disorder is behavioural impulsivity. This study assessed the ability of chronic acetyl-L-carnitine (ALC, saline or 100 mg/kg SC, plus 50 mg/kg orally) to reduce impulsivity in a validated animal model for ADHD. Food-restricted rats were tested during adolescence (postnatal days, pnd, 30-45) in operant chambers with two nose-poking holes, one delivering one food pellet immediately, and the other five pellets after a delay. Delay length was increased over days (from 0 to 80 s). Individual differences in the preference-delay curve emerged, with the identification of two distinct subpopulations, i.e. one with a nearly horizontal curve and another with a very steep ("impulsive") slope. The impulsivity profile was slightly but consistently reduced by chronic ALC administration. Consistent results were also obtained with methylphenidate (MPH, saline or 3 mg/kg IP twice daily). Impulsive rats exhibited a lower metabolite/serotonin (5HIAA/5HT) ratio in the medial frontal cortex (MFC) and lower noradrenaline (NA) levels in the MFC and cingulate cortex (CC) when compared with the other subgroup. The ALC treatment increased NA levels in the CC and the 5HIAA/5HT ratio in both CC and MFC. Present data suggest that ALC, a drug devoid of psychostimulant properties, may have some beneficial effects in the treatment of ADHD children.
Adriani
Walter
W
Behavioural Neuroscience Section, Dept. Cell Biology & Neurosciences, Istituto Superiore di Sanita', viale Regina Elena 299, 00161 Rome, Italy.
Rea
Monica
M
Baviera
Marta
M
Invernizzi
William
W
Carli
Mirjana
M
Ghirardi
Orlando
O
Caprioli
Antonio
A
Laviola
Giovanni
G
D000108:Acetylcarnitine / Q000494:pharmacology*; D000818:Animals; D001289:Attention Deficit Disorder with Hyperactivity / Q000188:drug therapy / Q000523:psychology; D001522:Behavior, Animal / Q000187:drug effects; D001923:Brain Chemistry / Q000187:drug effects; D000697:Central Nervous System Stimulants / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D007175:Impulsive Behavior / Q000188:drug therapy* / Q000523:psychology; D008297:Male; D008774:Methylphenidate / Q000494:pharmacology; D018697:Nootropic Agents / Q000494:pharmacology*; D009638:Norepinephrine / Q000378:metabolism; D017397:Prefrontal Cortex / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D012701:Serotonin / Q000378:metabolism
D000697:Central Nervous System Stimulants; D018697:Nootropic Agents; D008774:Methylphenidate; D012701:Serotonin; D000108:Acetylcarnitine; D009638:Norepinephrine