[Pharmacological studies on the cough reflex].

The artificially induced cough reflex in experimental animals should necessarily be similar to the cough which occurs naturally in humans. The curve demonstrated during a cough of each patient with respiratory disease was characteristic. Compared with the curve of a cough-like reflex (CLR) induced by DMPP, the curve of a cough induced by electrical stimulation of the tracheal mucosa was similar to that of a cough in humans. In dogs and cats anesthetized with alpha-chloralose (80 similar to 100 mg/kg i.p.), the number of CLR with DMPP was dose dependent. Tachphylaxis did not occur despite repeated administration of DMPP. DMPP (5 similar to 10 mug/kg i.v.) did not affect airway resistance. CLR with DMPP was depressed not only by morphine, codeine, oxymethebanol, picoperidamine, piclobetol and hexacol but also by hexamethonium. Thus, it appears that the mechanism of CLR with DMPP is different from that in the cough reflex. This CLR may be utilized for determining the physiology of cough reflex and the site of action of antitussives.