AJP - Gastrointestinal and Liver Physiology, Vol 263, Issue 2 248-G253, Copyright © 1992 by American Physiological Society
Preservation and propagation of cyclic myoelectric activity after feeding in rat small intestine
M. E. Zenilman, J. E. Parodi and J. M. Becker
Department of Surgery, Washington University School of Medicine, St. Louis, Missouri 63110.
The cyclic nature and distal propagation of the fasting migrating motor
complex (MMC) of the small intestine have been well described. The fate of
the MMC after feeding, however, has not been elucidated. We used time
series analysis with fast Fourier transforms (FFT) to study myoelectric
cycling before and after feeding. Ten rats were chronically prepared with
bipolar electrodes secured to the duodenum and proximal jejunum. Spikeburst
frequency was recorded before and after feeding simple nutrients. During
fasting, cyclic activity occurred at the MMC frequency. Although after
feeding this periodicity appeared disrupted, FFT analysis showed persistent
cycling at the fasted (MMC) rate. Digital filtering of data at the MMC
frequency isolated cycling from background noise during both fasted and fed
states and showed a depression in the amplitude of the waveform after
feeding. Root-mean-square analysis of the waveform confirmed statistically
significant depression of amplitude by 47-57%. The waveform propagated from
the duodenum to the jejunum during both the fasted and fed state at an
unchanged rate. We conclude that factors controlling myoelectric cycling
during the fasted state persist after feeding, allowing continued net
abroad propulsion of food.
