ANTITUSSIVE EFFECT OF CAPTOPRIL, AN ANGIOTENSIN-CONVERTING ENZYME-INHIBITOR, IN THE RAT

The effects of acute treatment with captopril, an angiotensin converti ng enzyme inhibitor, on the capsaicin-induced cough reflex were examin ed in rats. Intraperitoneal injection of captopril in doses of 3 and 1 0 mg/kg decreased the number of coughs dose-dependently. Although the peak effect was similar to that of morphine (0.5 mg/kg), the duration of captopril's effect (10 mg/kg) was longer than that of morphine. Fur thermore, while pretreatment with naloxone significantly decreased the duration of the antitussive effect of captopril, it had no significan t effect on the early-phase (within 60 min) effect of capotpril. These results suggest that the mechanism which underlies the antitussive ef fect of captopril involves mediation by both non-opioid and opioid sys tems.