Effect of d-pseudoephedrine on cough reflex and its mode of action in guinea pigs.
d-Pseudoephedrine (PSE) is one of the main ingredients of Ephedrae herba. Although PSE is widely applied for patients with a common cold and upper respiratory inflammation as a decongestant, the effects of PSE on cough have never been reported. In this study, we investigated the antitussive effects of intraperitoneal injection of PSE on the cough reflex induced by microinjection of citric acid into the larynx of guinea pigs. PSE decreased the number of cough reflexes dose-dependently (-18.3 +/- 5.0% at 20 mg/kg, P<0.05; -41.1 +/- 7.2% at 60 mg/kg, P<0.01). Furthermore, PSE (60 mg/kg) increased the threshold intensity for inducing fictive cough by electrical micro-stimulation of the nucleus tractus solitarius (+72.7 +/- 8.4%, P<0.01). On the afferent discharge of the superior laryngeal nerve, PSE suppressed the increases of amplitude and frequency when stimulated by citric acid at laryngeal mucosa. These results demonstrate that PSE possesses an antitussive effect that might be derived from both central and peripheral actions.
Minamizawa
Kiyoshi
K
Department of Japanese Oriental Medicine, Faculty of Medicine, University of Toyama, Japan.
Goto
Hirozo
H
Ohi
Yoshiaki
Y
Shimada
Yutaka
Y
Terasawa
Katsutoshi
K
Haji
Akira
A
D000818:Animals; D000996:Antitussive Agents; D001993:Bronchodilator Agents / Q000494:pharmacology*; D019343:Citric Acid; D003371:Cough / Q000139:chemically induced / Q000503:physiopathology*; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D004809:Ephedrine / Q000494:pharmacology*; D006168:Guinea Pigs; D007823:Laryngeal Nerves / Q000187:drug effects / Q000502:physiology; D007830:Larynx; D008297:Male; D008845:Microinjections; D009092:Mucous Membrane / Q000187:drug effects / Q000502:physiology; D012018:Reflex / Q000187:drug effects*; D017552:Solitary Nucleus / Q000502:physiology
D000996:Antitussive Agents; D001993:Bronchodilator Agents; D019343:Citric Acid; D004809:Ephedrine