Bronchodilating effects of bambuterol on bronchoconstriction in guinea pigs.
OBJECTIVE
To study the effects of bambuterol (Bam) on bronchoconstriction in guinea pigs.


METHODS
Bronchospasm induced by histamine aerosol, lung resistance (RL) and dynamic lung compliance (Cdyn) changes induced by ovalbumin aerosol in vivo, isolated resting lung parenchyma strips, and carbamylcholine-induced tracheal constriction in vitro in guinea pig were investigated.


RESULTS
Bam dose-dependently prolonged the time to histamine-induced collapse, ED50 values (95% confidence limits) of Bam intragastric gavage (i.g.) after 1 h, 4 h, and 24 h were 0.74 (0.60-0.91), 0.75 (0.61-0.91) and 1.00 (0.77-1.30) mg.kg-1, respectively. Bam 2 or 10 mg.kg-1 i.g. 2 h before ovalbumin aerosol partly or almost completely inhibited bronchial challenge of ovalbumin-induced change of RL and Cdyn. Bam 0.1-1.0 mumol.L-1 gave a weak relaxation on isolated tracheal strips induced by carbamylcholine and failed to relax the isolated resting lung parenchyma strips in guinea pig.


CONCLUSIONS
Bam showed a long-acting bronchodilation by its slow metabolism in vivo.
Xie
Q M
QM
Zhejiang Respiratory Drugs Research Laboratory, Administrative Center of New Drug Research & Development, State Pharmaceutical Administration of China, Zhejiang Medical University, Hangzhou, China.
Zeng
L H
LH
Zheng
Y X
YX
Lu
Y B
YB
Yang
Q H
QH
D000818:Animals; D001986:Bronchial Spasm / Q000139:chemically induced / Q000517:prevention & control; D016084:Bronchoconstriction / Q000187:drug effects*; D001993:Bronchodilator Agents / Q000494:pharmacology*; D005260:Female; D006168:Guinea Pigs; D006632:Histamine; D008170:Lung Compliance / Q000187:drug effects; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D013726:Terbutaline / Q000031:analogs & derivatives* / Q000494:pharmacology; D014132:Trachea / Q000187:drug effects
D001993:Bronchodilator Agents; D006632:Histamine; D013726:Terbutaline; C047766:bambuterol