Roach were tested, and finally Karjalainen approach chosen [11]. (With Karjalanen approach QTc interval was independent on HR, which was not the case with Bazett’s of Friedricia’s corrections [23] [24].)DiscussionThe main finding of the present study suggests impact of 5HTTLPR polymorphism on the relation between QTc interval and the brain 5-HTT binding; while QTc interval was significantly related to thalamus and temporal 5-HTT binding in l homozygotes, no association was found in s carriers. 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 [26]. Naringin biological activity stellatum blockade in healthy individuals was associated with the length of QTc interval [13]. 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 [27] [20]. 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 [28]. In humans electric stimulation of vagus nerve via auricular nerve induced similarly QT and HR shortening [12]. One study showed the effect of QTc prolongation along with significant HR increase with systemic sympathetic stimulation [29]. More detailed study showed prolongation of QTc interval after right stellatum blocade, and the opposite effect, after the left side blockade [13]. 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 [3]. Imaging studies have not been able to show direct gene effect from 5-HTTLPR to the brain 5-HTTbinding [8]. Still, there is robust evidence for the significance of 5HTTLPR on the brain structure and function: increased amygdala activity, increased amygdala stress responsiveness, reduced gray matter volume in perigenual anterior cingulate cortex, diminished corticolimbic structural co-variation, andStatistical AnalysisResults are presented as means 6 SD. Mann-Whitney twotailed tests were used for group comparisons of the data, when indicated. Pearson and Spearman correlations were used, when indicated. Using Bonferroni correction P,0.008 was taken to be statistical significant with a two tailed test. To identify those variables which are likely associated to QTc interval variation we employed linear regression analysis and multiple regression model, cluster-corrected to take into account the sampling of twins within twin pairs and thus provide correct standard errors and p-values [25]. SPSS 19.0 (SPSS Inc, Chicago, U.S.A.) and Stata (JSI-124 biological activity StataCorp, Texas, U.S.A.) programs were used for statistical analysis of the data.ResultsAutomatic detection of the QTc interval failed for three subjects (two l homozygotes and one s allele carrier). Basic characteristics of the study participants and nor-b-CIT binding values are presented in Tables 1 and 2. Means of body mass index, HR and QTc interval (n = 27) were not significantly different between l homozygotes and s carriers (T.Roach were tested, and finally Karjalainen approach chosen [11]. (With Karjalanen approach QTc interval was independent on HR, which was not the case with Bazett’s of Friedricia’s corrections [23] [24].)DiscussionThe main finding of the present study suggests impact of 5HTTLPR polymorphism on the relation between QTc interval and the brain 5-HTT binding; while QTc interval was significantly related to thalamus and temporal 5-HTT binding in l homozygotes, no association was found in s carriers. 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 [26]. Stellatum blockade in healthy individuals was associated with the length of QTc interval [13]. 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 [27] [20]. 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 [28]. In humans electric stimulation of vagus nerve via auricular nerve induced similarly QT and HR shortening [12]. One study showed the effect of QTc prolongation along with significant HR increase with systemic sympathetic stimulation [29]. More detailed study showed prolongation of QTc interval after right stellatum blocade, and the opposite effect, after the left side blockade [13]. 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 [3]. Imaging studies have not been able to show direct gene effect from 5-HTTLPR to the brain 5-HTTbinding [8]. Still, there is robust evidence for the significance of 5HTTLPR on the brain structure and function: increased amygdala activity, increased amygdala stress responsiveness, reduced gray matter volume in perigenual anterior cingulate cortex, diminished corticolimbic structural co-variation, andStatistical AnalysisResults are presented as means 6 SD. Mann-Whitney twotailed tests were used for group comparisons of the data, when indicated. Pearson and Spearman correlations were used, when indicated. Using Bonferroni correction P,0.008 was taken to be statistical significant with a two tailed test. To identify those variables which are likely associated to QTc interval variation we employed linear regression analysis and multiple regression model, cluster-corrected to take into account the sampling of twins within twin pairs and thus provide correct standard errors and p-values [25]. SPSS 19.0 (SPSS Inc, Chicago, U.S.A.) and Stata (StataCorp, Texas, U.S.A.) programs were used for statistical analysis of the data.ResultsAutomatic detection of the QTc interval failed for three subjects (two l homozygotes and one s allele carrier). Basic characteristics of the study participants and nor-b-CIT binding values are presented in Tables 1 and 2. Means of body mass index, HR and QTc interval (n = 27) were not significantly different between l homozygotes and s carriers (T.