[The effect of epithelium on inhibition of histamine-induced contraction of guinea-pig isolated trachea by potassium channel opener Rp 52891].
To evaluate whether the relaxant effect of Rp 52891 on isolated normal or sensitized guinea-pigs trachea is influenced by the removal of airway epithelium, twenty-four normal and sensitized guinea-pigs were randomly divided into two groups: epithelium-intact trachea and epithelium-denuded trachea. The effect of Rp 52891 on contraction elicited by histamine in epithelium-intact and epithelium-denuded trachea was investigated, and it was compared with that of aminophylline or isoprenaline. The results revealed that there was no significant difference in histamine-induced contractile response between normal and sensitized isolated trachea. The inhibitory effect of Rp 52891 on the contractile response of histamine was significantly reduced by removing the epithelium but that of aminophylline or isoprenaline was not changed. These results suggested that Rp 52891 may directly relax the airway smooth muscle of guinea-pigs in vitro, the epithelium of guinea-pigs trachea may modulate the relaxant effect of Rp 52891.
Lu
Y
Y
Department of Respiratory Medicine, Changzheng Hospital, 2nd Military Medical University, Shanghai.
Luo
W
W
Shi
Z
Z
D000628:Aminophylline / Q000494:pharmacology; D000818:Animals; D001993:Bronchodilator Agents / Q000494:pharmacology*; D004848:Epithelium / Q000503:physiopathology; D005260:Female; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects*; D010847:Picolines / Q000494:pharmacology*; D015221:Potassium Channels; D011714:Pyrans / Q000494:pharmacology*; D011897:Random Allocation; D014132:Trachea / Q000187:drug effects
D001993:Bronchodilator Agents; D010847:Picolines; D015221:Potassium Channels; D011714:Pyrans; D000628:Aminophylline; C061043:aprikalim; D007545:Isoproterenol