1 6 



Scientific Proceedings (77). 



12 (1190) 



The action of succinate, malate, tartrate and citrate on the 



isolated intestine. 



By William Salant, C. W. Mitchell, and E. W. Schwartze. 



[From the Pharmacological Laboratory, Bureau of Chemistry, 

 Washington, D. C] 



Segments of the isolated intestine of the rabbit suspended in 

 Locke's solution and containing sodium succinate exhibited in- 

 creased activity in concentrations of iV/30 to N/200. Stimulation 

 was also observed in N/10 succinate, but this was usually preceded 

 by primary depression. Sodium malate in concentrations of N/10 

 and iV/30 caused depression, the rhythmic contractions disappear- 

 ing almost entirely for a period of several minutes. This was 

 followed, however, by improvement while the intestinal segments 

 were still in contact with the salt. Stimulation was observed in 

 tests with iV/70 to iV/100 sodium malate. Sodium tartrate dextro 

 in Locke's solution produced the following results: A solution of 

 N/10 made up by adding the salt to Locke's solution caused 

 promptly a drop of tonus; rhythmic contractions became weak or 

 disappeared entirely for a few minutes. The fact was less marked, 

 however, with the same concentration of tartrate when it was 

 substituted for an equivalent amount of sodium chloride. In this 

 case a moderate decrease only of amplitude without a change of 

 tonus in the small intestine was noticed. The large intestine 

 showed a marked decrease of tonus and complete disappearance 

 of rhythmic contractions. With weaker concentrations of tar- 

 trate, such as N/20 to iV/50 a decrease of tonus was obtained, 

 which was greater in segments of the large intestine, the effect 

 diminishing with increase in dilution. The rhythmic contractions 

 were usually augmented in force, especially in the ileum, the effects 

 being the same with isosmotic and with hypertonic solutions. 



Observations on the action of citrate indicated that a solution 

 of N/4.00 may increase the force of the contractions and sometimes 

 also the tonus. The effect was different with more concentrated 



