AJP - Gastrointestinal and Liver Physiology, Vol 272, Issue 4 916-G922, Copyright © 1997 by American Physiological Society
Rhythmic oscillating complexes in gastrointestinal tract of chickens: a role for motilin
A. Rodriguez-Sinovas, M. Jimenez, P. De Clercq, T. L. Peeters and P. Vergara
Department of Cell Biology and Physiology, Veterinary Faculty, Universitat Autonoma de Barcelona, Bellaterra, Spain.
Rhythmic oscillating complex (ROC) is a highly organized gastrointestinal
motility pattern recently described in fasted avian species. ROCs show
several high-speed aborad-propagated contractions that progressively change
into others of orad direction. In addition, chickens show migrating motor
complexes (MMC) in both fed and fasting states. Recently, motilin was
isolated and characterized from chicken small intestine. Accordingly, the
aim of this study was to learn whether chicken motilin might be involved in
either ROC or MMC induction. Electromyographic recordings were obtained
from different areas of the gastrointestinal tract of chickens while
motilin was infused. The response to chicken motilin was dose dependent in
both fed and fasted animals; a bolus of 4 x 10(-11) mol/kg (n = 5) did not
modify the intestinal motor pattern, whereas 4 x 10(-10) and 4 x 10(-9)
mol/kg (n = 5 each) induced a complete ROC pattern of 5.2 +/- 0.6 and 10.8
+/- 0.9 min, respectively. ROCs induced by chicken motilin presented
exactly the same pattern as that described during a spontaneous ROC.
Furthermore, motilin concentration in plasma, measured by radioimmunoassay,
increased during a spontaneous ROC. This study suggests that chicken
motilin triggers an ROC in chickens. The fact that plasma motilin levels
increased during spontaneous ROC strongly suggests that motilin is involved
in the induction of the ROC pattern. Motilin seems to play a different role
in avian and mammalian species, because a phase III of the MMC was never
induced by motilin infusion.
