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Media type:
E-Article
Title:
EXPERIMENTS ON THE SURVIVING MAMMALIAN INTESTINE
Contributor:
Gunn, James A.;
Underhill, S. W. F.
imprint:
Wiley, 1914
Published in:Quarterly Journal of Experimental Physiology
Language:
English
DOI:
10.1113/expphysiol.1914.sp000183
ISSN:
0370-2901
Origination:
Footnote:
Description:
<jats:p>Segments of the small intestine have been kept exsected at different temperatures to determine for how long a period the pendulum movements can be revived when the intestine is subsequently put into oxygenated Locke's solution at 37° C.; also to determine what modifications the pendulum movements undergo when revived under these conditions, and what alterations occur in the effects produced on them by certain drugs.</jats:p><jats:p>As far as has been found, the maximum time of survival is as follows: 5 days when the isolated intestine is kept at 3° to 7° C.; over 24 hours when kept at about 15° C.; at least 8½ hours when kept at 37° C. (without oxygen).</jats:p><jats:p>The movements of the revived intestine show a gradual diminution of amplitude, but no conspicuous alteration of rate.</jats:p><jats:p>The reaction of the revived intestine to adrenine and to barium continues unchanged at those temperatures so long as the intestine retains any power of rhythmic movement. Pilocarpine and atropine produce their normal action on the pendulum movements when the intestine is kept for 5 days at 3° to 7° C.; but lose their effect when it is kept for 3½ hours at 37° C.</jats:p><jats:p>The results give an indication of the longevity of the receptive substances for those drugs when the intestine is kept at different temperatures, and lead to the conclusion that the receptive substances connected with the sympathetic nerve terminals have a greater vitality than those connected with the parasympathetic nerve terminals.</jats:p><jats:p>The isolated circular muscle of the cat's small intestine possesses the power of executing rhythmic movements, resembling the pendulum movements, when it is completely separated from the longitudinal muscle on the one side and from the submucosa and mucous membrane on the other. This power is retained even when the outer layers of the circular muscle have also been removed; the inner layers, remote from Auerbach's plexus, still retain the property of spontaneous rhythmicity.</jats:p><jats:p>Subject to a revision of the accepted conceptions of the localised nature of Auerbach's plexus, the conclusion is drawn that the spontaneous rhythmicity of these movements is an inherent property of the muscle itself. This conclusion is supported by the fact that, when the intestine is kept at different temperatures, the power of executing rhythmic movements and the power of reacting to barium disappear at the same time.</jats:p><jats:p>The movements of the isolated muscularis mucosæ of the cat's small intestine have been recorded and found to consist of regular slow rhythmic contractions, occurring at the rate of one in 27 to 60 seconds.</jats:p><jats:p>Those movements bear a general resemblance to the rhythmic contractions of the spleen, and probably have a similar function of accelerating the local circulation. Adrenine has a motor effect on the rhythmic contractions of the muscularis mucosæ, as on those of the spleen.</jats:p><jats:p>The benefit of adrenine as a styptic in gastric ulcer may be due partly to its arresting capillary hæmorrhage by contracting the muscularis mucosæ.</jats:p>