Enteric mechanisms of initiation of migrating myoelectric complexes in dogs. 1983

S Sarna, and R E Condon, and V Cowles

The enteric mechanisms governing initiation of migrating myoelectric complexes were studied in 6 conscious dogs, each implanted with a set of 12 bipolar electrodes on the small intestine. The small intestine was transected and reanastomosed at three sites to give four isolated segments of equal length. Each segment had three implanted electrodes. All four isolated segments generated migrating myoelectric complexes which were, initially, totally independent of each other in time. The most proximal segment had the longest mean migrating myoelectric complex time period (106.2 +/- 10.1 SEM min) and the second segment had the shortest mean migrating myoelectric complex time period (66.8 +/- 6.7 SEM min). Distal to the second segment, the mean migrating myoelectric complex time period increased progressively (83.1 +/- 11.2 SEM min and 95.8 +/- 7.6 SEM min, respectively). Isolation of the small intestine into segments did not significantly change migrating myoelectric complex propagation characteristics such as velocity and direction of propagation within each segment. The mean duration of phase 3 activity was not affected in the first segment but increased significantly in the distal three segments (p less than 0.05). The propagation of migrating myoelectric complexes across the sites of transection and reanastomosis started recovering 45-60 days after surgery and recovered fully by 98-108 days. The study findings show that enteric mechanisms control the initiation of migrating myoelectric complexes. Each small segment of the small intestine is capable of initiating migrating myoelectric complexes of its own and behaves as a relaxation oscillator. In the intact small intestine, regional migrating myoelectric complex oscillators are coupled by the intrinsic neurons so that the proximal oscillators drive the distal oscillators. Recovery of migrating myoelectric complex propagation across sites of transection and reanastomosis suggest that intrinsic nerves regenerate after transection.

UI MeSH Term Description Entries
D007421 Intestine, Small The portion of the GASTROINTESTINAL TRACT between the PYLORUS of the STOMACH and the ILEOCECAL VALVE of the LARGE INTESTINE. It is divisible into three portions: the DUODENUM, the JEJUNUM, and the ILEUM. Small Intestine,Intestines, Small,Small Intestines
D004285 Dogs The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065) Canis familiaris,Dog
D004594 Electrophysiology The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.
D000200 Action Potentials Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli. Spike Potentials,Nerve Impulses,Action Potential,Impulse, Nerve,Impulses, Nerve,Nerve Impulse,Potential, Action,Potential, Spike,Potentials, Action,Potentials, Spike,Spike Potential
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia

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