Nature 166, 734 (28 October 1950); doi:10.1038/166734a0

Effect of Indole and some Indolic Compounds on Muscle Sensitivity to Acetylcholine and Potassium

J. A. IZQUIERDO & A. O. M. STOPPANI

Institute of Physiology, Faculty of Medicine, Buenos Aires. June 18.

AMONG the indolic compounds formed from tryptophane in animal intestine, indole, skatole and indolethylamine are those reported to have the strongest pharmacological action. Their effect on plain or striated muscle has been studied in the past, either in vivo or in the isolated organs, although with no clear and consistent results^1–5. More recently, Torda and Wolff⁶ have examined the effect of indole, skatole, indole-3-acetate and tryptophane on the sensitivity of frog striated muscle to acetylcholine and potassium, finding that only indole increases the response to acetylcholine, while indole, skatole and indoleacetate increase the potassium effect. Since the presence in the bowel of indole and allied compounds seems to be a normal fact⁷, and that the intestinal membrane can absorb and fix significant amounts of indole⁸, and presumably other indole compounds as well, it seemed interesting to study their effect on the intestinal smooth muscle, as it might have implications in regard to the alterations of intestine motility.

1. Yanai, B. , Tohoku J. Exp. Med., 25, 385, 401, 407 (1935). | ChemPort |
2. Waddell, J. A. , J. Pharm., 31, 205 (1927). | ChemPort |
3. Ets, H. N. , and Feinberg, I. M. , Amer. J. Physiol., 136, 646 (1942).
4. Garcia Blanco, J. , del Castillo, J. , and Rodeles, J. F. , Rev. Soc. argent. Biol., 17, 473 (1941). | ChemPort |
5. Guggenheim, M. , and Löffler, W. , Biochem. Z., 72, 303 (1916). | ChemPort |
6. Torda, C. , and Wolff, H. G. , Amer. J. Physiol., 145, 608 (1945). | ISI |
7. Alvarez, W. C. , Physiol. Rev., 4, 352 (1924).
8. Nicolai, H. , Klin. Wschr., 21, 108 (1942). | Article | ChemPort |
9. Crumpler, T. B. , and Yoe, J. H. , "Chemical Computations and Errors" (London: Chapman and Hall, Ltd., 1940).