title: Mouth rinsing and ingestion of a bitter-tasting solution increases corticomotor excitability in male competitive cyclists.
abstract: OBJECTIVE
  Recently, we have shown that the combination of mouth rinsing and ingesting a bitter-tasting quinine solution immediately prior to the performance of a maximal 30-s cycling sprint significantly improves mean and peak power output. This ergogenic effect was proposed to be related to the activation of the corticomotor pathway by afferent taste signals originating from bitter taste receptors in the oral cavity. The aim of the present study was to use single-pulse transcranial magnetic stimulation to investigate whether mouth rinsing and ingestion of a bitter quinine solution increases corticomotor excitability.
  
  
  METHODS
  A series of 10 motor-evoked potentials (MEPs) were recorded from the relaxed first dorsal interosseus muscle in 16 male competitive cyclists immediately before and after they rinsed their mouth for 10 s and then ingested either a 2 mM bitter quinine solution or plain water.
  
  
  RESULTS
  Mean MEP amplitude was significantly increased in response to quinine administration by 16% (p < 0.05), with no evidence of a time-dependent effect over the 10 pulses. Mean MEP amplitude also increased by 10% in response to water administration (p < 0.05), though this increase was significantly smaller than the response to quinine (p < 0.05).
  
  
  CONCLUSIONS
  We conclude that the activation of bitter taste receptors in the oral cavity and upper gastrointestinal tract has the capacity to increase corticomotor excitability in male competitive cyclists.
authors.affiliation: School of Sport Science, Exercise and Health, The University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia. SharonGam22@gmail.com.
authors.forename: Sharon
authors.identifier: http://orcid.org/0000-0002-9475-5089
authors.initials: S
authors.lastname: Gam
authors.affiliation: School of Sport Science, Exercise and Health, The University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia.
authors.forename: Kym J
authors.initials: KJ
authors.lastname: Guelfi
authors.affiliation: School of Psychology, The University of Western Australia, Crawley, Australia.
authors.forename: Geoff
authors.initials: G
authors.lastname: Hammond
authors.affiliation: School of Sport Science, Exercise and Health, The University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Fournier
mesh_terms: D000328:Adult; D054874:Athletic Performance; D004435:Eating; D019054:Evoked Potentials, Motor / Q000187:drug effects*; D006801:Humans; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D009067:Mouthwashes / Q000737:chemistry / Q000494:pharmacology; D009125:Muscle Relaxants, Central / Q000008:administration & dosage / Q000494:pharmacology*; D018482:Muscle, Skeletal / Q000502:physiology*; D011803:Quinine / Q000008:administration & dosage / Q000494:pharmacology*; D013649:Taste; D050781:Transcranial Magnetic Stimulation
chemical_list: D009067:Mouthwashes; D009125:Muscle Relaxants, Central; D011803:Quinine
keywords: Bitter taste; Motor cortex; Motor-evoked potential facilitation; Quinine; Transcranial magnetic stimulation