title: Familial studies of heritability of alpha1-adrenergic receptor responsiveness in superficial veins.
abstract: BACKGROUND
  Studies of monozygotic and dizygotic twins indicate an important genetic influence on the variability of responsiveness to norepinephrine in superficial human vein.
  
  
  OBJECTIVE
  Genetic aspects of variability of alpha1-adrenergic receptor responsiveness to norepinephrine in superficial veins were further investigated by studying the response to norepinephrine in the dorsal hand veins of parents and their children.
  
  
  METHODS
  Subjects were healthy nonsmoking adults (n = 24; age range, 40 to 52 years) and their biological children (n = 20; age range, 15 to 26 years) who were free from medications likely to modify vascular tone. Superficial vein responsiveness to norepinephrine was assessed by the linear variable differential transformer technique. The dose of norepinephrine required to constrict superficial vein diameter by 50% from baseline (ED50) was calculated for each subject. Heritability was estimated by standard techniques of regression of mid-parent/child (natural logarithm) ED50 values.
  
  
  RESULTS
  ED50 ranged from 5.6 to 254.6 ng/min in the parents and from 7.8 to 242.3 ng/min in the children. Heritability was calculated at 0.88.
  
  
  CONCLUSIONS
  These data confirm wide variability in superficial vein responsiveness to norepinephrine. The results confirm a major genetic influence in biological responsiveness of superficial vein to norepinephrine in healthy humans. Heritability of vascular alpha-adrenergic receptor responsiveness may influence vascular regulation during sympathetic stimulation and blockade.
authors.affiliation: Department of Medicine, University of Western Ontario, London, Canada.
authors.forename: A
authors.initials: A
authors.lastname: Gupta
authors.forename: S G
authors.initials: SG
authors.lastname: Carruthers
mesh_terms: D000293:Adolescent; D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000328:Adult; D004305:Dose-Response Relationship, Drug; D005192:Family Health; D005260:Female; D006225:Hand; D006801:Humans; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000494:pharmacology*; D018340:Receptors, Adrenergic, alpha-1 / Q000187:drug effects / Q000235:genetics*; D012044:Regression Analysis; D014661:Vasoconstriction / Q000187:drug effects / Q000235:genetics*; D014680:Veins / Q000187:drug effects / Q000378:metabolism*
chemical_list: D000316:Adrenergic alpha-Agonists; D018340:Receptors, Adrenergic, alpha-1; D009638:Norepinephrine