Clinicians long have observed that the hay fever patient is vulnerable to asthma. But neither the mechanism of this progression nor the interrelationship of the two ailments are understood.
Evidence that asthma is governed by a quantitative effect on the autonomic nervous system was presented to the American Academy of Allergy by two University of Wisconsin investigators.
The mechanism of the increased bronchial reactivity that characterizes asthma, said John J. Ouellette, MD, is increased blockage of beta adrenergic sites.
With the aid of 11 volunteers having a history of hay fever but not asthma, it was shown that asthmatic responses could be produced.
A chief stimulus for the experiment was the observation that propranolol, used in treatment of angina, hyperthyroid state, and other disorders, caused rapid, acute airway obstruction in asthmatics.
The agent has a specific beta adrenergic blocking action.
Patients in the test had been undergoing ragweed therapy for