title: [Vegetative cardiac rhythm regulation as a function of the morning melatonin levels in teenagers-northerners on a background of mental effort].
abstract: Seventy normal 12-15 y.o. teenagers in the Arkhangelsk oblast of Russia (in latitude 61 north) were investigated in the pubertal period (June, September, December). Immune-enzyme analysis was used to determine melatonin levels in blood serum at 8.30-9.30 a.m. In the daytime, cardiac rhythm variability was assessed on a background of mental calculation. It was shown that morning melatonin in blood serum of teenagers-northerners may be indicative of sympathetic cardiac rhythm regulation, particularly during mental effort. In June (the longest light period) the vegetative regulation had a minimal effect on mental effort. Dependence of the sympathetic activity on the level of morning melatonin in teenagers was conspicuous in September when the light period shortens.
authors.forename: L V
authors.initials: LV
authors.lastname: Poskotinova
authors.forename: E V
authors.initials: EV
authors.lastname: Krivonogova
authors.forename: D B
authors.initials: DB
authors.lastname: Demin
mesh_terms: D000293:Adolescent; D001110:Arctic Regions; D002648:Child; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D006321:Heart / Q000294:innervation*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008550:Melatonin / Q000097:blood*; D008603:Mental Health; D012426:Russia; D012621:Seasons; D013564:Sympathetic Nervous System / Q000502:physiology*
chemical_list: D008550:Melatonin