Correlation between increased bronchial responsiveness to histamine and diminished plasma cyclic adenosine monophosphate response after epinephrine in asthmatic children. Diminished plasma cyclic adenosine monophosphate response after epinephrine in moderate childhood asthma.

The respiratory threshold to histamine and the plasma cyclic adenosine monophosphate (AMP) every 5 min for 40 min after subcutaneous epinephrine were determined in 21 children with moderate bronchial asthma who were without symptoms at the time of study. There was a statistically significant correlation between a high respiratory sensitivity to histamine and a low plasma cyclic AMP response to epinephrine. The plasma cyclic AMP response was compared with that in 16 control subjects. The asthmatic patients had significantly diminished responses; the difference was greatest for the values 25 min after stimulation. This study supports the hypotheses that the bronchial hyperresponsiveness in asthma is due partly to a defective beta adrenergic system and that the defect is permanent, existing also during periods without symptoms or medication and in patients with moderate asthma.