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Bronchodilation by halothane is not modulated by airway epithelium
A Sayiner1, R R Lorenz, D O Warner
1Mayo Clinic, Rochester, Minnesota 55905.
Anesthesiology
|July 1, 1991
Summary
Halothane relaxes airway smooth muscles, but its effects are not modulated by the airway epithelium. This study found halothane
Area of Science:
- Anesthesiology
- Pulmonary Physiology
- Pharmacology
Background:
- Airway smooth muscle relaxation is a key effect of halothane.
- The role of airway epithelium in mediating halothane's effects is not fully understood.
Purpose of the Study:
- To investigate whether the airway epithelium modulates the smooth muscle relaxant effects of halothane.
- To determine if halothane's impact on bronchial responsiveness differs in the presence or absence of airway epithelium.
Main Methods:
- Isolated canine bronchial rings and segments were used, with and without epithelium.
- Tissues were contracted using acetylcholine, 5-hydroxytryptamine, electrical field stimulation, or carbachol.
- Effects of 1 and 2 MAC halothane on contractility and relaxation were assessed.
Main Results:
- Epithelium removal increased sensitivity to acetylcholine and 5-hydroxytryptamine but not electrical field stimulation.
- Halothane (1 and 2 MAC) decreased sensitivity to acetylcholine, 5-hydroxytryptamine, and electrical field stimulation in both intact and de-epithelialized tissues.
- No significant difference in halothane's effect was observed between tissues with and without epithelium.
Conclusions:
- The airway epithelium does not modulate the relaxant effects of halothane on canine airway smooth muscle.
- Halothane's bronchodilatory effects are independent of the presence of airway epithelium.