Effect of d-Pseudoephedrine on Cough Reflex and Its Mode of Action in Guinea Pigs

Abstract

Abstract. 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.

Molecular Analysis and Chemical Evaluation of Ephedra Plants in Mongolia

“…Further investigation of the regulatory mechanism on formation of these two compounds is ongoing. PEph was reported to have effect of anti-tussive, anti-inflammation and other effects, 4,26) suggesting the usefulness of Mongolian Ephedra plants to relieve rhinitis and nasal congestion.…”

“…2) Pharmacological studies revealed central nervous system (CNS) stimulation, anti-tussive, decongestion, anti-inflammatory activities of ephedrine and its analogue, [3][4][5][6] providing the scientific basis underlying its traditional uses. Besides traditional usage in Asia, it has also been used as a dietary supplement in U.S.A. and Europe in recent years.…”

Tosse: neurofisiologia, métodos de pesquisa, terapia farmacológica e fonoaudiológica

“…Nos trabalhos experimentais a tosse pode ser provocada pela microestimulação elétrica direta do núcleo do trato solitário após descerebração (26), ou por estimulação mecânica/elétrica da mucosa das vias aéreas em animais conscientes ou sob anestesia geral.…”

“…Entretanto, a naloxona, antagonista desses receptores, não impede a ação antitussígena da codeína no gato (14). É possível, então, que os narcóticos atuem também em receptores nãoopioides -talvez de glutamato, serotonina ou nociceptina -no SNC (17,26).…”

“…A codeína é um dos antitussígenos mais eficazes, porém comumente provoca efeitos colaterais (náuseas, constipação intestinal) e pode causar dependência (26).…”