Action of Xanthin on Isolated Intestine. 15 



11 (1189) 



The action of xanthin and methyl xanthins on the isolated intestine. 



By William Salant and E. W. Schwartze. 



[From the Pharmacological Laboratory, Bureau of Chemistry, 

 Washington, D. C] 



The tests were made with different concentrations of xanthin 

 and its derivatives dissolved in Locke's solution which were carried 

 out on segments of different parts of the intestine of the rabbit. 

 Sodium xanthin in concentrations of 1 : 2,000 and 1 : 1,000 

 caused increased tonus which was more pronounced in the large 

 than in the small intestine. The rhythmic contractions also 

 improved under these conditions but this effect was not constant. 

 Experiments with solutions of 1 : 10,000 sodium xanthin were 

 negative or produced a slight stimulating action. All the methyl 

 derivatives when employed in concentrations of 1 : 2,000 and 

 1 : 1 ,000 produced marked depression of the rhythmic movements 

 and of tonus. The effect of higher concentrations varied. A 

 solution of 1 : 10,000 caffein caused moderate stimulation of the 

 movements of the small intestine but had no effect on the large 

 intestine. This concentration of theobromin proved to be a 

 much greater stimulant while theophyllin 1 : 10,000 induced ir- 

 regular action in the small intestine with lowered tonus and 

 disappearance of contractions in the large intestine. In still 

 greater dilutions, however, as 1 : 50,000 theophyllin produced a 

 marked increase in the force of the contraction of the small 

 intestine. Similar results were obtained with 1 : 25,000 theo- 

 bromin, but tests with 1 : 25,000 caffein proved to be negative. 



