Variation of slow-wave frequency and locking during the migrating myoelectric complex in dogs.
Slow waves determine rhythm and polarity of spike bursts. We measured the variation of slow-wave frequency (swf) and locking (swl) in the canine jejunum during the various phases of the migrating myoelectric complex (MMC) and during induced phase III (erythromycin 125 micrograms/kg iv bolus or somatostatin 2.5 micrograms.kg-1.h-1 iv infusion), blocked phase III (atropine 20 micrograms/kg iv bolus), and so-called stationary phase III activity (cisapride 150 micrograms/kg iv bolus). The EMG of 4 dogs, implanted with 10 bipolar electrodes, was recorded on a polygraph. Our results indicate that swf and swl change during the MMC from a stepwise swf gradient with slow waves locked in plateaus during phase I to a continuous swf gradient without or with significantly reduced phase locking during phase III. The length of the first swf plateau decreases significantly from 42 +/- 12 cm post Treitz during phase I to 11 +/- 4 cm during spontaneous phase III. Atropine block of phase III activity prevents phase unlocking and development of a continuous swf gradient. Our hypothesis is that phase unlocking may be one of the induction mechanisms of spike-burst activity.
Department of Internal Medicine and Medical Research, Rega Institute, University of Leuven, Belgium.
P
P
Caenepeel
W
W
Janssens
A
A
Accarino
J
J
Janssens
G
G
Vantrappen
H
H
Eyssen
D000818:Animals; D004285:Dogs; D004566:Electrodes; D004594:Electrophysiology; D007583:Jejunum / Q000502:physiology*; D016065:Myoelectric Complex, Migrating / Q000502:physiology*; D013004:Somatostatin / Q000502:physiology
D013004:Somatostatin