Effects of popcorn butter flavorings, diacetyl and 2,3‐pentanedione, on isolated airway preparations

Abstract

RATIONALE“Popcorn workers’ lung” is a life‐threatening, fixed obstructive pulmonary disease caused by inhalation of butter flavoring vapor. Histological evidence from animals exposed by inhalation to the butter flavorings, diacetyl (2,3‐butanedione), and a diacetyl substitute, 2,3‐pentanedione (acetyl proprionyl), demonstrated vapor‐concentration‐dependent damage to epithelial cells. Because nothing is known about the effects of diacetyl and 2,3‐pentanedione on airway smooth muscle (ASM), we investigated the pharmacological activity of these two flavorings on isolated airways.METHODSIn rat isolated, perfused tracheas, the contractile and relaxant effects of diacetyl and 2,3‐pentanedione applied to the serosal and mucosal surfaces of intact and denuded contracted (MCh; 3×10−5 M) tracheas were evaluated.RESULTSConcentrations of both agents greater than 3 mM resulted in ASM relaxation. Relaxation of the trachea by diacetyl and 2,3‐pentanedione was not dependent upon the presence of the epithelium.CONCLUSIONSOur findings indicate that both flavorings are similar in their effects as ASM relaxants.