AJP - Gastrointestinal and Liver Physiology, Vol 266, Issue 4 585-G595, Copyright © 1994 by American Physiological Society
Rhythmic oscillating complex: characterization, induction, and relationship to MMC in chickens
M. Jimenez, V. Martinez, A. Rodriguez-Membrilla, A. Rodriguez-Sinovas, E. Gonalons and P. Vergara
Department of Cell Biology and Physiology, Veterinary Faculty, Universitat Autonoma de Barcelona, Bellaterra, Spain.
Migrating myoelectrical complexes (MMCs) and rhythmic oscillating complexes
(ROCs) have been investigated in chickens prepared for electromyography.
Animals were chronically implanted with electrodes in stomach, duodenum,
jejunum, ileum, ceca, and rectum. MMCs showing phases I-III were found in
the jejunum and ileum both in fed and fasted states. Repetitive spike
bursts were recorded in the duodenum (0.5-1/h), disrupting the
gastroduodenal coordination and preceding a phase III in the jejunum. ROCs
appeared spontaneously in fasted animals and in 75% of the recordings
during the dark period. Four consecutive intestinal myoelectrical patterns
have been described during a ROC. Briefly, they consisted in series of
high-speed propagated abroad contractions of great amplitude that
progressively changed into others of orad direction. In relation to the
MMC, the ROC pattern appeared just after a phase III reached the distal
ileum, and a pattern of duodenal repetitive spike bursts, followed by a
migrating phase III in the jejunum, started at the duodenum after a ROC. No
myoelectrical changes were recorded in cecorectal activity during ROC.
Vagotomized animals showed the ROC pattern. Neither apomorphine (5-100
micrograms/kg iv) nor cholecystokinin (10(-9) mol/kg iv) induced ROCs.
Naloxone (5 x 10(-7) mol/kg iv) and atropine (0.1 mg/kg iv) induced
isolated orad contractions. Myoelectrical and functional similarities can
be found between retrograde giant contractions, described in mammals, and
ROCs. However, they differ in their origin and mechanism of induction.
