A semi quantitative method for cyclic nucleotide localization by immunocytochemistry and its application in determining the distribution of cyclic AMP in lungs of normal and pertussis-vaccinated mice following histamine or epinephrine challenge

Abstract

A method is described which allows quantitative comparison of cAMP content determined by immunocytochemical procedures. This technique was then employed to localize cAMP in lungs of normal and pertussis-vaccinated mice following saline, histamine, or epinephrine challenge. All primary pulmonary compartments were shown to contain some immunoreactive (cAMP) material. However, epinephrine and histamine challenge selectively increased the cAMP content of the vasculature. No effect of epinephrine or histamine was detected in bronchial smooth muscle or interstitial tissue. This increased cAMP accumulation was observed in both normal and pertussis-vaccinated mice following epinephrine challenge but only in pertussis-vaccinated mice after histamine administration. These results demonstrate that histamine and epinephrine stimulate cAMP accumulation in the same pulmonary compartments supporting earlier speculation that histamine acts indirectly through epinephrine release. Further, primary involvement of the vasculature supports a more prominent role for this tissue in pertussis mediated histamine hypersensitivity.