TY - JOUR
T1 - A preliminary report on dopamine system reactivity in PKU
T2 - Acute effects of haloperidol on neuropsychological, physiological, and neuroendocrine functions
AU - Luciana, Monica
AU - Hanson, Karen L.
AU - Whitley, Chester B.
N1 - Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2004/8
Y1 - 2004/8
N2 - Background: Classic phenylketonuria (PKU) is due to an inborn error of metabolism resulting in an inability to metabolize the amino acid phenylalanine. To avoid mental retardation, affected individuals observe a phenylalanine-restricted diet. When dietary control is poor, deficits in prefrontally mediated cognitive functions have been observed. It has been suggested that these deficits are due to disruptions in the mesocortical dopamine system that projects to the prefrontal cortex. Methods: In this study, dopamine system reactivity was examined in individuals with PKU, relative to age-matched controls, using the non-specific DA antagonist haloperidol, in a repeated measures placebo-controlled design. Outcome variables included neuroendocrine, physiological, and cognitive measures. Results: Regardless of drug condition, PKU participants differed from control participants in their blood phenylalanine and tyrosine levels, and in their times to complete measures of attention and working memory. Also, relative to placebo, haloperidol influenced several variables irrespective of group status, including serum prolactin secretion, times to complete attention and working memory tasks, and accuracy of working memory performance. An interaction between group and drug condition was observed for the digit span task, where PKU participants exhibited greater relative impairments on haloperidol. When composite indices of impairment were derived, PKU participants demonstrated selective disruption in executive function on haloperidol relative to control subjects. Conclusions: Findings are consistent with the presence of frontostriatal dysfunction in PKU but are less consistent with the notion that PFC dopamine function is specifically affected.
AB - Background: Classic phenylketonuria (PKU) is due to an inborn error of metabolism resulting in an inability to metabolize the amino acid phenylalanine. To avoid mental retardation, affected individuals observe a phenylalanine-restricted diet. When dietary control is poor, deficits in prefrontally mediated cognitive functions have been observed. It has been suggested that these deficits are due to disruptions in the mesocortical dopamine system that projects to the prefrontal cortex. Methods: In this study, dopamine system reactivity was examined in individuals with PKU, relative to age-matched controls, using the non-specific DA antagonist haloperidol, in a repeated measures placebo-controlled design. Outcome variables included neuroendocrine, physiological, and cognitive measures. Results: Regardless of drug condition, PKU participants differed from control participants in their blood phenylalanine and tyrosine levels, and in their times to complete measures of attention and working memory. Also, relative to placebo, haloperidol influenced several variables irrespective of group status, including serum prolactin secretion, times to complete attention and working memory tasks, and accuracy of working memory performance. An interaction between group and drug condition was observed for the digit span task, where PKU participants exhibited greater relative impairments on haloperidol. When composite indices of impairment were derived, PKU participants demonstrated selective disruption in executive function on haloperidol relative to control subjects. Conclusions: Findings are consistent with the presence of frontostriatal dysfunction in PKU but are less consistent with the notion that PFC dopamine function is specifically affected.
KW - Dopamine
KW - Phenylketonuria
KW - Prefrontal
KW - Working memory
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U2 - 10.1007/s00213-004-1775-0
DO - 10.1007/s00213-004-1775-0
M3 - Article
C2 - 15024549
AN - SCOPUS:4544290690
SN - 0033-3158
VL - 175
SP - 18
EP - 25
JO - Psychopharmacology
JF - Psychopharmacology
IS - 1
ER -