ИСТИНА

that require self-motivation and internal cues in the absence of demonstrable cognitive failure or motor weakness. So development of the mental fatigue is the significant problem for people who work with big amount of data and constantly need focused attention. Molecular mechanisms of MF origin still are not clear. It is known that basal ganglia play a key role in the development of MF (Chaudhuri et al., 2000). Dopamine is one of the most prevalent neurotransmitters in the basal ganglia. Therefore we suppose that alterations in the functioning of dopamine system provided by genes variations may influence the development of the MF. We tested the hypothesis that allelic variation of the DRD2 and DAT genes located mostly in the striatum could be associated with differences in the onset of MF. In current investigation 160 volunteers (78 males and 82 females) participated. Subjects were genotyped for TaqI A RFLP of the DRD2 gene and 40-bp VNTR polymorphism of the DAT gene. Psychophysiological indexes were measured before and after mental load consisted in the monotonous passing of personality questionnaires during three hours. Case-control analyses suggested a strong association between the A1+10/10 genotype and increased mental fatigue (P < 0.05). In conclusion, mental fatigue seems to be related to allelic variations within the DRD2 and DAT genes.