Contrasting effects of ATP and adenosine on capsaicin challenge in asthmatic patients
Küçük Resim Yok
Tarih
2017
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Academic Press Ltd- Elsevier Science Ltd
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
Background: Adenosine 5'-triphosphate (ATP) stimulates pulmonary vagal slow conducting C-fibres and fast conducting A delta-fibres with rapidly adapting receptors (RARs). Pulmonary C-fibres but not RARs are also sensitive to capsaicin, a potent tussigenic agent in humans. Thus, the aim of this study was to determine the effects of ATP and its metabolite adenosine (given as adenosine 5'-monophosphate, AMP) on capsaicin challenge in asthmatic patients. Methods: Cough (quantified as visual analogue scale, VAS), dyspnoea (quantified as Borg score), and FEVi were quantified following bronchoprovocation using capsaicin, adenosine and ATP in healthy nonsmokers (age 40 +/- 4y, 6 males), smokers (45 +/- 4y, 5 males) and asthmatic patients (37 +/- 3y, 5 males); n = 10 in each group. Results: None of the healthy non-smokers responded to either AMP or ATP. AMP induced bronchoconstriction in one smoker and eight asthmatics, and ATP in two smokers and all ten asthmatics. The geometric mean of capsaicin causing >= 5 coughs (C5) increased from 134 to 203 mu M in non-smokers and from 117 to 287 mu M in asthmatics after AMP, whereas it decreased from 203 to 165 mu M and 125 to 88 mu M, respectively after ATP. AMP decreased C5 from 58 to 29 mu M and ATP increased from 33 to 47 mu M in smokers. However, due to intergroup variability, these effects of ATP and AMP were not statistically significant (0.125 <= p <= 0.998). That notwithstanding, in healthy and asthmatic subjects the effects of the ATP showed a tendency to be greater than those of AMP (p < 0.053). Dyspnea, assessed by Borg score, increased after ATP (p < 0.001) and AMP (p < 0.001) only in asthmatic patients. Intensity of cough assessed by VAS increased (p < 0.05) after second capsaicin challenges performed after AMP in all groups, but not after ATP. Conclusions: Asthmatic patients exhibit hypersensitivity to aerosolized AMP and ATP, but aerosolized AMP does not mimic the effects of ATP and the effects of ATP are not mediated by adenosine. 2017 Published by Elsevier Ltd.
Açıklama
Anahtar Kelimeler
Asthma, Cough, Puirinergic receptors, Vagus
Kaynak
Pulmonary Pharmacology & Therapeutics
WoS Q Değeri
Q3
Scopus Q Değeri
Q2
Cilt
45
