title: Pharmacogenetic Effects of Inhaled Salbutamol on 10-km Time Trial Performance in Competitive Male and Female Cyclists.
abstract: OBJECTIVE
  To determine the effects of single nucleotide polymorphisms (SNPs) in the adrenergic β2-receptor gene (ADRB2, rs1042713, and rs1042714) and epithelial Na channel gene (SCNN1A, rs2228576) on cycling performance after the inhalation of salbutamol.
  
  
  METHODS
  Randomized double-blind, mixed-model repeated measures.
  
  
  METHODS
  University Research Setting.
  
  
  METHODS
  Sixty-nine trained (maximal oxygen consumption: 62.3 ± 7.6 mL·kg·min) male and female cyclists, aged 19 to 40 years.
  
  
  METHODS
  Participants performed two 10-km time trials 60 minutes after the inhalation of 400 μg of salbutamol or placebo. Subjects were genotyped for the three SNPs (rs1042713: AA 8, AG 30 GG 31; rs1042714: CC 19, CG 35, GG 15; rs2228576: GG: 31 GA: 34 AA: 4).
  
  
  METHODS
  Forced expiratory volume in 1 second (FEV1) was assessed immediately before and 30 minutes after inhalation. Performance was measured by mean power output maintained over the duration of the time trial.
  
  
  RESULTS
  There was a significant increase in FEV1 after the inhalation of salbutamol [mean (SD) = 5.68% (4.7)] compared with placebo [0.84% (2.8); P < 0.001]; however, this did not lead to an improvement in 10-km cycling time trial performance. Neither the bronchodilatory response nor the time trial performance after salbutamol was affected by genotype at any of the 3 SNPs.
  
  
  CONCLUSIONS
  In cyclists, FEV1 was significantly improved after salbutamol administration regardless of genotypic variation at the ADRB2 (rs1042713 and rs1042714) and SCNN1A (rs2228576) genes. Despite this improvement in lung function, 10-km time trial performance was not altered after the inhalation of salbutamol.
  
  
  CONCLUSIONS
  Our findings did not show genotype-dependent differences in bronchodilatory responses and athletic performance to inhaled salbutamol, suggesting that genotype-specific drug therapy will not improve asthmatic athletes' care nor athletic performance.
authors.affiliation: *School of Kinesiology, Faculty of Education, University of British Columbia, Vancouver, British Columbia, Canada; and †Division of Sport Medicine, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Sarah
authors.initials: S
authors.lastname: Koch
authors.forename: Martin J
authors.initials: MJ
authors.lastname: MacInnis
authors.forename: James L
authors.initials: JL
authors.lastname: Rupert
authors.forename: Benjamin C
authors.initials: BC
authors.lastname: Sporer
authors.forename: Michael S
authors.initials: MS
authors.lastname: Koehle
mesh_terms: D000280:Administration, Inhalation; D058666:Adrenergic beta-2 Receptor Agonists / Q000494:pharmacology*; D000328:Adult; D000420:Albuterol / Q000494:pharmacology*; D054874:Athletic Performance; D001642:Bicycling; D004311:Double-Blind Method; D053503:Epithelial Sodium Channels / Q000235:genetics*; D005080:Exercise Test; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D058573:Performance-Enhancing Substances; D000071184:Pharmacogenomic Variants; D018343:Receptors, Adrenergic, beta-2 / Q000235:genetics*; D055815:Young Adult
chemical_list: C553443:ADRB2 protein, human; D058666:Adrenergic beta-2 Receptor Agonists; D053503:Epithelial Sodium Channels; D058573:Performance-Enhancing Substances; D018343:Receptors, Adrenergic, beta-2; C507045:SCNN1A protein, human; D000420:Albuterol