| Abstrakt: |
Koinaroff1reported that carnosine, B-alanyl-1-histidine, produced a marked increase in the tonus of isolated rabbit intestine. McClintock and Hines2confirmed this observation and also noted that carnosine caused a similar increase in tonus and rhythmical contractions of the isolated guinea pig uterus. Contrary to this view is the work of McClosky, et al.,3who were unable to substantiate the reported oxytocic effect of carnosine on uterine strips.In the light of the somewhat conflicting work on uterine strips, we thought it would be worthwhile to reinvestigate the smooth muscle action of carnosine.∗In the present work, isolated monkey†intestine was used. Oxygenated Tyrode's solution served as a physiological bath for these experiments. The temperature was kept at 37.5°C. Forty-eight experiments using various doses of carnosine were performed. Fig. 1 illustrates the typical effect as noted with 1.5 mg of this drug in a 100 cc bath.For a long time we have been interested in the fact that morphine causes a relaxation of the isolated intestine in various animals, but markedly stimulates the tone of the intact intestine. While many workers, Dreyer,4Gruber, et al.,5and others have reported a stimulating effect of morphine on isolated intestine, we have never consistently obtained such results. Rather, it has been our belief that in isolated tissue some necessary substance was lacking which prevented morphine from giving a typical response such as is seen in the intact animal. To test this hypothesis, 25 experiments were done on the isolated monkey intestine using morphine alone. Fig. 2 exemplifies the usual response; i. e., relaxation. When carnosine was given previously, however, a large dose of morphine did not cause relaxation (Fig. 3). |
