Histamine Release From Human Lung by a Component of Cotton Bracts

Abstract

Tyrode-soluble extracts of cotton bracts, pericarps, and fibers, and compound 48/80 were tested for their capacity to release histamine in vitro from chopped human autopsy lung. Average total histamine was 12.61 μg/gm (N = 25). Average histamine released nonspecifically (control), with bracts extract or with compound 48/80 was, respectively, 1.72 (N = 25), 0.47 (N = 8), 4.17 (N = 25) micrograms per gram of lung per 30 minutes. No release was obtained from extracts of pericarps or fibers. Bracts extract contained a steam volatile component that released an average of 1.20 (N = 9) micrograms histamine per gram of lung at 30 minutes. This component had similar physicochemical behavior to methyl piperonylate. Synthetic methyl piperonylate released histamine from chopped human lung when incubated at 5 × 10^-11 to 5 × 10^-5M. The optimum concentration was 5 × 10^-8M when the average release of histamine was 1.35 (N = 4) micrograms per gram of lung per 30 minutes. Histamine release by methyl piperonylate was stimulated by propranolol hydrochloride and inhibited by isoproterenol hydrochloride and theophylline thus implicating a role for cyclic adenosine monophosphate in the release process.