Effect of Various Amino Acids on Motility of Excised Segments of the Small Intestine

Abstract

Summary and Conclusion

The results with aspartic and glutamic acids are the same as those reported by Hirschfelder and Cantwell even though much weaker solutions were used in our experiments. Their explanation, that the depressant action is probably due to a decrease in pH was checked and found to hold also for the present work. Alanine and phenylalanine exerted only a slight temporary depressing action despite the fact that the molar concentration of the alanine was much higher than that of either aspartic or glutaniic acid.

Since the bacterial cultures used in the previous work by Weinstein and Rettger were alkaline in reaction and the amino acids, when neutralized, had no effect on intestinal motility, as judged by experiments of the type here described, it must be concluded that the depressant action of the bacterial cultures was not due to their content of amino acids.