Use of multichannel electrointestinography for noninvasive assessment of myoelectrical activity in the cecum and large colon of horses.
OBJECTIVE
To evaluate whether changes in myoelectrical activity in the cecum and large colon of horses can be detected via multichannel electrointestinography (EIG).


METHODS
6 healthy mature horses.


METHODS
Each horse underwent 3 EIG procedures. Intestinal myoelectrical activity (cecum and large colon) was recorded during a 20-minute period following i.v. administration of physiologic saline (0.9% NaCl) solution (20 mL; baseline), erythromycin lactobionate (0.5 mg/kg), or detomidine (0.015 mg/kg); intestinal contractions were concurrently viewed via B-mode ultrasonography. By use of computer software, 8-channel EIG recordings were analyzed and the mean of the dominant frequency (a measure of the rhythmicity of gastric electrical activity) expressed in cycles per minute (cpm) was obtained. Total power (muV(2)) was calculated, and treatment effect was expressed as the power ratio (ie, treatment-associated power divided by the baseline power).


RESULTS
The dominant frequency cpm values were not stable, and no significant differences between treatments were detected. Compared with the effects of saline solution treatment, detomidine significantly reduced the mean cecal and colonic power ratios. Erythromycin significantly reduced the cecal power ratio and increased the colonic power ratio, although the increase was significant in only 1 channel. Ultrasonographic findings and total power (predominantly from the long-distance electrode pairs) were significantly correlated.


CONCLUSIONS
In horses, EIG was useful for assessment of changes in myoelectrical activity in the cecum and large colon. Multiple electrodes should be used to cover a larger area of the intestine, and agreement between multiple channels is needed to make the analysis meaningful.
Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1, Canada.
Judith B
JB
Koenig
Christina E W
CE
Martin
Stephanie G
SG
Nykamp
Martin P
MP
Mintchev
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000818:Animals; D002432:Cecum / Q000000981:diagnostic imaging / Q000187:drug effects / Q000502:physiology*; D003106:Colon / Q000000981:diagnostic imaging / Q000187:drug effects / Q000502:physiology*; D018592:Cross-Over Studies; D004576:Electromyography / Q000187:drug effects / Q000662:veterinary*; D004917:Erythromycin / Q000031:analogs & derivatives / Q000494:pharmacology; D005765:Gastrointestinal Agents / Q000494:pharmacology; D005769:Gastrointestinal Motility / Q000187:drug effects / Q000502:physiology; D006736:Horses / Q000502:physiology*; D007093:Imidazoles / Q000494:pharmacology; D016065:Myoelectric Complex, Migrating / Q000187:drug effects / Q000502:physiology*; D014463:Ultrasonography
D000316:Adrenergic alpha-Agonists; D005765:Gastrointestinal Agents; D007093:Imidazoles; C010948:erythromycin lactobionate; D004917:Erythromycin; C041255:detomidine