Airway smooth muscle and platelet responses to several varieties of cotton bracts.

Abstract

Aqueous extracts of several varieties of cotton bracts were tested for their ability to: (1) contract isolated canine airways, and (2) cause 5-hydroxy-tryptamine (5-HT) release from human platelets. With regard to airway contractions, the order of effectiveness was: Lambright GL-4=Early Cot WR=LX-571>Texas Mix>Acala SJ-2>Coker 310. The EC50 for Coker 310 was approximately 6 times greater than that for Lambright GL-4. With regard to 5-HT release from platelets, the order of effectiveness was: LX-571=Acala SJ-2>Lambright GL-4>Coker 310>Early Cot WR>Texas Mix. The EC50 for Texas Mix was approximately 15 times greater than that for LX-571. There was no correlation between the EC50’s for smooth muscle contraction and the EC50’s for 5-HT release. We conclude that the concentrations of the bronchoactive and platelet active factors vary considerably among bracts obtained from different varieties of cotton. Moreover, bracts that contain a high concentration of the bronchoactive factor do not necessarily contain a high concentration of the platelet active factor, and vice-versa.