Hyperresponsiveness to autacoids and autonomic drugs in lung parenchymal strips from sensitized guinea pigs

The responsiveness of lung parenchymal strips isolated from actively sensitized guinea pigs to some selected autacoids (histamine, 5-hydroxytryptamine, bradykinin, and prostaglandins F2 alpha and l2) and autonomic drugs (acetylcholine, norepinephrine, methoxamine, and isoprenaline) was compared with that of strips from unsensitized animals. The concentration-response curves to the agonists, with the only exception of isoprenaline, in the sensitized group exhibited a left upward displacement (greater maximal effects and less effective concentration 50%) compared with those obtained in the unsensitized group. These results indicate the existence of a nonspecific increase in responsiveness of lung parenchymal strip isolated from sensitized animals.