Behavioral phenotypes of impulsivity related to the ANKK1 gene are independent of an acute stressorReport as inadecuate




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Behavioral and Brain Functions

, 4:54

First Online: 24 November 2008Received: 12 September 2008Accepted: 24 November 2008

Abstract

BackgroundThe A1 allele of the ANKK1 Taq IA polymorphism previously reported as located in the D2 dopamine receptor DRD2 gene is associated with reduced DRD2 density in the striatum and with clinical disorders, particularly addiction. It was hypothesized that impulsivity represents an endophenotype underlying these associations with the Taq IA and that environmental stress would moderate the strength of the gene-behavior relationship.

MethodsTaq IA genotyping was conducted on 72 healthy young adults who were randomly allocated to either an acute psychosocial stress or relaxation induction condition. Behavioral phenotypes of impulsivity were measured using a card-sorting index of reinforcement sensitivity and computerized response inhibition and delay discounting tasks.

ResultsSeparate analyses of variance revealed associations between the A1 allele and two laboratory measures of impulsivity. The presence of the Taq IA allele A1+ was associated with slower card-sorting in the presence of small financial reinforcers, but was overcome in a second administration after either a five-minute rest or psychosocial stress induction. A1+ participants also demonstrated significantly poorer response inhibition and faster response times on a computerized stop inhibition task, independent of acute stress exposure.

ConclusionThese findings indicate the A1 allele is associated with an endophenotype comprising both a -rash impulsive- behavioral style and reinforcement-related learning deficits. These effects are independent of stress.

Electronic supplementary materialThe online version of this article doi:10.1186-1744-9081-4-54 contains supplementary material, which is available to authorized users.

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Author: Melanie J White - C Phillip Morris - Bruce R Lawford - Ross McD Young

Source: https://link.springer.com/







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