Abstract
The lungs of female guinea pigs, either untreated or previously sensitized with aqueous extracts of cotton dust (AECD) were perfused via the pulmonary artery with 0, 10−6, 10−5 or 10−4 g/mL of lyophilized AECD in Tyrodes solution. Pressure changes in the pulmonary artery were monitored during this period. After perfusion, the pulmonary parenchyma was excised, frozen, and later analyzed for c-AMP, c-GMP, histamine, and total protein. Levels of c-AMP and histamine decreased while levels of c-GMP and pulmonary arterial pressure increased with increasing doses of AECD. Correlation coefficients, between the parameters measured, indicate that the ratio of c-AMP to c-GMP (c-AMP/c-GMP) was a better indicator of histamine depletion or change in pulmonary arterial pressure than was the level of either c-AMP or c-GMP alone. Comparisons of the relative changes in c-AMP, c-GMP, c-AMP/c-GMP, histamine, and pulmonary arterial pressure between sensitized and nonsensitized guinea pigs support the hypothesis that the acute changes in pulmonary function that follow breathing of cotton dust are due to the effects of pharmacoactive compounds and not to antigen-antibody response.