Abstract
BackgroundThe A1 allele of the ANKK1 TaqIA 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 TaqIA and that environmental stress would moderate the strength of the gene-behavior relationship.MethodsTaqIA 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 TaqIA 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.
Highlights
The A1 allele of the ANKK1 TaqIA 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, addiction
The presence of the A1 allele of the TaqIA polymorphism in the ANKK1 gene [9] (i.e., A1A1 and A1A2 genotypes) has been associated with reduced D2 dopamine receptor (DRD2) density in key structures linked to brain reinforcement, in the striatum
The TaqIA had been historically described as residing in the D2 dopamine receptor (DRD2) gene but has more recently been referred to as being within the ANKK1 [9]
Summary
The A1 allele of the ANKK1 TaqIA 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, addiction. The presence of the A1 allele of the TaqIA polymorphism (rs1800497) in the ANKK1 gene [9] (i.e., A1A1 and A1A2 genotypes) has been associated with reduced D2 dopamine receptor (DRD2) density in key structures linked to brain reinforcement, in the striatum This association has been confirmed by both in vitro [10,11] and in vivo positron emission tomography (PET) studies [12,13]. The TaqIA had been historically described as residing in the D2 dopamine receptor (DRD2) gene but has more recently been referred to as being within the ANKK1 [9] In addition to these biological associations, a strong body of evidence suggests the involvement of the A1 allele in a range of behavioral disorders characterized by impulsivity, including severe alcohol and other substance abuse, obesity, pathological gambling and ADHD [14,15,16]. More direct evidence in rats supports an association between reduced D2 receptor availability in the ventral striatum and trait reinforceroriented impulsivity [19]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
