Effect of clenbuterol on sulfur dioxide-induced acute bronchitis in guinea pigs.
When guinea pigs were exposed to sulfur dioxide (SO2) gas (800 ppm, 2 h), they showed hyperresponsiveness to intravenously administered serotonin (5-hydroxytryptamine (5-HT)). This hyperresponsiveness continued for over 24 h after the exposure to the gas. The degeneration, desquamation of epithelium, and edema of the lamina propria of the trachea and bronchi were observed in animals after a 2-h exposure of SO2 histopathologically. These changes seemed to be the early phase of acute bronchitis. Then, we examined the effect of clenbuterol, a selective beta-2 adrenoceptor agonist, on the SO2-induced bronchial hyperresponsiveness in these animals. Orally administered clenbuterol (1-10 micrograms/kg) suppressed the hyperresponsiveness to 5-HT in a dose-dependent manner. These results suggest that clenbuterol might inhibit the hyperresponsiveness that accompanies acute bronchitis and that this agent may be useful for remission of broncho-spasm.
Ito
M
M
Pharmaceuticals Development Research Laboratory, Teijin Institute for Bio-Medical Research, Tokyo, Japan.
Kaniwa
T
T
Horiuchi
H
H
Nonaka
T
T
Yamanaka
Y
Y
Uno
H
H
Kishimoto
T
T
Kiyoki
M
M
D000208:Acute Disease; D000818:Animals; D001980:Bronchi / Q000187:drug effects / Q000473:pathology; D016535:Bronchial Hyperreactivity / Q000139:chemically induced / Q000517:prevention & control; D001991:Bronchitis / Q000139:chemically induced / Q000188:drug therapy*; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry / Q000166:cytology; D002976:Clenbuterol / Q000627:therapeutic use*; D006168:Guinea Pigs; D007958:Leukocyte Count; D008297:Male; D012701:Serotonin / Q000494:pharmacology; D013458:Sulfur Dioxide; D014132:Trachea / Q000187:drug effects / Q000473:pathology
D013458:Sulfur Dioxide; D012701:Serotonin; D002976:Clenbuterol