Impact of 5-HTTLPR polymorphism on the 5-HTT AbMole Povidone iodine binding in the human brain. Both significant associations and findings with no association have been reported . Instead of direct gene effect on the brain 5-HTT binding, certain patterns of coupling of central nervous functions and structures are more clearly determined by 5-HTTLPR polymorphism. For example, there may be higher structural covariance between amygdala and anterior cingulate in individuals with both long alleles than in s allele carriers, and also there may be higher baseline amygdala activity with exaggerated responses to stressful images in s carriers than in l homozygotes. It has been hypothesized that 5-HTTLPR polymorphism causes these structural and functional variations by influencing on the timing and duration of 5-HTT gene expression. In the present study young healthy adults were examined to assess the impact of 5-HTTLPR polymorphism on the functional integration in terms of relations between the brain 5-HTT binding and cardiovascular function, i.e. heart rate, and heart rate corrected QT interval. We were particularly interested on the relations between QTc interval and brain norb-CIT binding, as we noticed the association between QTc interval and striatum nor-b-CIT binding in partially the same, but larger sample, but this finding remained without satisfactorial explanation. The present study reanalyzes this interrelation with genotype data, which with functional connectivity context brings essentially new light to understand the relation. QTc interval is also particularly interesting compared with other measurements from ECG, because QTc interval is partially controlled by autonomic nervous system.As s allele in 5HTTLPR polymorphism has been related to less intra brain functional connectivity, we hypothesised similarly divergent pattern of integration between QTc interval and the brain 5HTT binding by 5-HTTLPR polymorphism. There is some evidence for associations between cardiac repolarization and the brain function, linking QTc interval to brain and efferent autonomic physiology. In a large series of patients with prior brain infarction, the location of right or left insula for brain infarction was associated with abnormal cardiac repolarization. Stellatum blockade in healthy individuals was associated with the length of QTc interval. To our knowledge, the association between the brain 5-HTT binding and QTc interval is a novel finding. With a limitation of small sample size this relation is based on high repeatability of both QTc interval and 5-HTT binding in the thalamus. The association is most likely related to autonomic control of cardiovascular system, rather than other factors which regulate QTc interval. Parasympathetic blockade with atropine induced attenuation of QT shortening in HIS bundle paced dogs. In humans electric stimulation of vagus nerve via auricular nerve induced similarly QT and HR shortening. One study showed the effect of QTc prolongation along with significant HR increase with systemic sympathetic stimulation. More detailed study showed prolongation of QTc interval after right stellatum blocade, and the opposite effect, after the left side blockade. The relation between the brain 5-HTT binding and QTc interval was dictated by 5-HTT genotype in the present study. The influence of s allele was dominantly inhibited gene transcription in vitro. Imaging studies have not been able to show direct gene effect from 5-HTTLPR to the brain 5-HTTbinding.