Effect of CO2 induced pH changes on the response of isolated guinea pig tracheas to isoproterenol.

This study was undertaken to examine the influence of carbon dioxide induced pH changes on the sensitivity of guinea pig airway smooth muscle to isoproterenol. The data indicate that alkalotic changes in media pH (pH 7.6 and 7.8) caused a significant decrease in the sensitivity of the airway to the beta-agonist when the tissue was at basal tone. When precontracted with histamine, however, acidosis (pH 7.0 and 7.2) enhanced, and alkalosis (pH 7.8) diminished the sensitivity of the smooth muscle to isoproterenol.