Bratisl Med J
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Inhalation of high concentration of oxygen produces a lung injury in men and experimental animals. In our previous experiment we have found suppression of cough reflex in healthy guinea pigs after an exposure to 100% O2 for 60 hours. This study was designed to find the effect of hyperoxia on cough reflex in guinea pigs with lungs damaged by bleomycin. ⋯ Cough was also induced by mechanical stimulation of laryngopharyngeal (LPh) and tracheobronchial (TBr) region in anaesthetized animals (Urethane, 1.1 g/kg, i.p.) just after the end of oxygen exposition and was evaluated from the interpleural pressure record. The results have shown a tendency to inhibition of citric acid cough reflex in animals 13 days treated with bleomycin and exposed to 100% O2, and significant decrease in citric acid induced cough in animals 20 days treated with bleomycin and exposed to 100% O2. Significant changes were present in cough intensity induced by mechanical stimulation of TBr region of the guinea pigs airway treated with bleomycin and exposed to oxygen, too. (Tab. 1, Fig. 3, Ref: 29.)
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Cough is the most important defence reflex of the airways. Little information exists about participation of the ion channels in the mechanism of the cough reflex. ⋯ Experimental results showed antitussive activity of the calcium-channel blocker diltiazem and suggested the role of voltage-gated calcium channels of type L in mechanism of the cough reflex. (Fig. 4, Ref. 15.).