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Antitussive activity of iodo-resiniferatoxin in guinea pigs
  1. M Trevisani1,
  2. A Milan1,
  3. R Gatti1,
  4. A Zanasi2,
  5. S Harrison1,
  6. G Fontana3,
  7. A H Morice4,
  8. P Geppetti1,3
  1. 1Center of Excellence for the Study of Inflammation, University of Ferrara, Ferrara, Italy
  2. 2Department of Thoracic-Pumonary Diseases, Unit of Respiratory Physiopathology, University of Bologna, Bologna, Italy
  3. 3Department of Critical Care Medicine and Surgery, University of Florence, Florence, Italy
  4. 4Academic Medicine, University of Hull, Hull, UK
  1. Correspondence to:
    M Trevisani PhD
    Center of Excellence for the Study of Inflammation, University of Ferrara, 44100 Ferrara, Italy;


Background: Iodo-resiniferatoxin (I-RTX) has recently been described as an ultra potent antagonist of the transient receptor potential vanilloid-1 (TRPV1).

Methods: The ability of I-RTX to inhibit cough induced by inhalation of two putative TRPV1 stimulants (capsaicin and citric acid) was tested in non-anaesthetised guinea pigs.

Results: Pretreatment with I-RTX either intraperitoneally (0.03–0.3 µmol/kg) or by aerosol (0.1–3 µM) reduced the number of coughs produced by inhalation of citric acid (0.25 M) and capsaicin (30 µM) in a dose dependent manner. Capsazepine (CPZ) also reduced citric acid and capsaicin induced cough, but the activity of I-RTX was 10–100 times more potent than CPZ in all the experimental conditions tested.

Conclusions: I-RTX is a novel and potent antitussive drug which inhibits cough mediated by agents possibly acting via TRPV1 activation.

  • ASIC, acid sensing ion channel
  • CPZ, capsazepine
  • I-RTX, iodo-resiniferatoxin
  • RAR, rapidly adapting receptor
  • TRPV1, transient receptor potential vanilloid-1
  • cough
  • guinea pig
  • vanilloid receptor-1 (TRPV1)
  • iodo-resiniferatoxin (I-RTX)

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  • This work was supported in part by ARCA, Padua and MUIR, Rome.