PT - JOURNAL ARTICLE AU - J. M. Parker AU - J. D. McColl AU - J. K. W. Ferguson TI - A COMPARISON OF THE BRONCHODILATOR ACTIVITY OF SOME 1-AND 7-SUBSTITUTED XANTHINES IN THE GUINEA PIG DP - 1956 Nov 01 TA - Journal of Pharmacology and Experimental Therapeutics PG - 359--364 VI - 118 IP - 3 4099 - http://jpet.aspetjournals.org/content/118/3/359.short 4100 - http://jpet.aspetjournals.org/content/118/3/359.full SO - J Pharmacol Exp Ther1956 Nov 01; 118 AB - A series of 1- and 7-substituted xanthines was studied in vitro for dilator activity in preventing bronchospasm from histamine or acetylcholine. Two of the most effective, 7-chloroethyl and 7-isoamyl theophylline, were compared to aminophylline in intact guinea pigs exposed to histamine or metacholine aerosols. The effectiveness of the compounds was very similar toward both the spasmogens. 7-Chloroethyl theophylline was the most potent compound tested, by both in vitro and in vivo tests.