Effects of dietary linoleic acid on beta-adrenergic responsiveness of the guinea pig respiratory system.

Respiratory autonomic beta-adrenergic receptor function was investigated in isolated tracheal spirals of guinea pigs receiving different diets. Comparison was made between control and Haemophilus influenzae treated animals; this latter group serving as animal model for atopy. The different semi-synthetic diets (35 energy%) varying in their linoleic acid contents (5.85, 11.25 and 22.05 en%), exerted profound effects on membrane fatty acid composition. No influence of these diets on either food intake or growth could be detected. Isoprenaline induced relaxation of guinea pig tracheal spirals was maximal in the dietary group receiving moderate linoleic acid (11.25 en%). Both the addition and the withdrawal of linoleic acid to this diet resulted in a significant impairment of beta-adrenergic receptor function, to the same extent as can be induced by Haemophilus influenzae. The results are discussed in view of current concepts for atopy.