The effect of cholinergic and anticholinergic agents on the primate model of allergic asthma

Rhesus monkeys with reagin-mediated, immediate-type respiratory responses to ascaris antigen were used for comparison with the type of responses that occur from certain pharmacologic agents. Carbacholine produces a respiratory response that is the same type as an antigen-induced respiratory response and will sensitize an animal's airway so that a dose of antigen not reactive alone will stimulate a response. Antigen and histamine will sensitize the airway so that a subthreshold dose of carbacholine will produce a respiratory response. Atropine completely inhibited the carbacholine response and reversed the increased sensitivity to carbacholine that occurs after an antigen response. Atropine did not block the antigen-induced respiratory response or the respiratory response to prostagladin F2alpha. Partial inhibition of these responses may have occurred but was not detected in the systems used in these studies. A double-antigen challenge system in the rhesus model of asthma provides a useful technique for evaluating the effect of pharmacologic agents on the reagin-mediated respiratory response.