Abstract
Introduction
There are substantial, phenotypical individual differences in the adverse impact of total sleep deprivation (TSD) on vigilant attention performance. Dopaminergic genotypes have been found to contribute to these phenotypical differences. Here we investigated the association between a single nucleotide polymorphism (SNP) of the dopamine receptor D2 (DRD2) gene, C957T (rs6277), on vigilant attention performance measured with the psychomotor vigilance test (PVT) in a laboratory TSD study.
Methods
N=46 healthy adults (ages 26.0±5.3y; 25 females) completed a 4-day in-laboratory study with a baseline day (10h time in bed: 22:00-08:00), a 38h TSD period, and a recovery day (10h time in bed: 22:00-08:00). DNA isolated from whole blood was assayed for DRD2 C957T genotype using real-time polymerase chain reaction. PVT performance was measured during TSD at 2-4h intervals, and analyzed for genotype using mixed-effects analysis of covariance of lapses of attention (RTs>500ms).
Results
The genotype distribution in this sample - 28.3% C/C, 50.0% C/T, 21.7% T/T - was found to be in Hardy-Weinberg Equilibrium (X21=0.0008, p=0.98). As expected, there was a significant effect of time awake on PVT performance (F14,602=26.67, p<0.001). There was a significant main effect of DRD2 genotype (F2,602=3.24, p=0.040) and a significant interaction of time awake by DRD2 genotype (F28,602=1.96, p=0.003). Subjects homozygous for the T allele showed greater impairment during extended wakefulness than carriers of the C allele. Genotype explained 7.6% of the variance in the PVT data observed during the 38h TSD period.
Conclusion
Subjects homozygous for the T allele of DRD2 C957T were considerably more vulnerable to TSD-induced PVT performance impairment than carriers of the C allele. A recent study showed that DRD2 C957T influences PVT performance in interaction with a SNP of the DAT1 gene. Here, DRD2 genotype was by itself also associated with PVT performance impairment during TSD.
Support
CDMRP awards W81XWH-16-1-0319 and W81XWH-18-1-0100.