THE MOTILITY OF THE ISOLATED GUINEA-PIG SMALL INTESTINE

Abstract

1. Employing the original as well as modified Trendelenburg's method and the intraluminal perfusion method the motility of the isolated small intestine of guinea pigs is studied.2. The evidences have been obtained that the preparatory phase is entirely of a physical nature, and that the preceding longitudinal shortening is produced because the loop is stretched along its longitudinal axis.3. With the increase of the intraluminal pressure the contraction waves are gradually increased in their strength and regulated to propagate from oral to anal, that is, coordinated, without showing any definite changes both in their period and velocity of propagation. On the basis of the results described above the concept according to which the critical intraluminal pressure produces an entirely new pattern of the movement, ‘peristalsis’, can not be accepted.4. Sooner or later after the removal of the loop there can, on raising the intraluminal pressure in a moderate degree, occur powerful contraction waves with a remarkably prolonged period. This kind of waves is characterized in that they are superimposed with small contractions which are nothing but pre-existing waves. Consequently the large waves are to be regarded as a summated effects of pre-existing waves, being produced as a result of deterioration of the preparation.5. After cooling the intestinal loop or cocainizing the mucosa of the loop, the loop always responds with uncoordinated contractions to a rise of the intra luminal pressure. From this it may be said that, when the intestine is released from the control of the intramural ganglion cells, its contractions lack the coordination.6. On the basis of the results obtained in the present experiment as well as the previous ones which are especially concerned with the function of the intramural ganglion cells a new hypothesis is postulated to explain how the strength as well as the direction of the waves of the small intestine can be regulated.