Circumferential and functional re-entry of in vivo slow-wave activity in the porcine small intestine
Article first published online: 11 MAR 2013
© 2013 Blackwell Publishing Ltd
Neurogastroenterology & Motility
Volume 25, Issue 5, pages e304–e314, May 2013
How to Cite
Angeli, T. R., O'Grady, G., Du, P., Paskaranandavadivel, N., Pullan, A. J., Bissett, I. P. and Cheng, L. K. (2013), Circumferential and functional re-entry of in vivo slow-wave activity in the porcine small intestine. Neurogastroenterology & Motility, 25: e304–e314. doi: 10.1111/nmo.12085
- Issue published online: 18 APR 2013
- Article first published online: 11 MAR 2013
- Manuscript Accepted: 26 DEC 2012
- Manuscript Received: 15 OCT 2012
- New Zealand Health Research Council
- National Institutes of Health. Grant Number: R01 DK64775
- the Riddet Institute
- Earle Food Research Fund
- Royal Society of New Zealand
- frequency gradient;
- high-resolution mapping;
- Interstitial cells of Cajal;
Slow-waves modulate the pattern of small intestine contractions. However, the large-scale spatial organization of intestinal slow-wave pacesetting remains uncertain because most previous studies have had limited resolution. This study applied high-resolution (HR) mapping to evaluate intestinal pacesetting mechanisms and propagation patterns in vivo.
HR serosal mapping was performed in anesthetized pigs using flexible arrays (256 electrodes; 32 × 8; 4 mm spacing), applied along the jejunum. Slow-wave propagation patterns, frequencies, and velocities were calculated. Slow-wave initiation sources were identified and analyzed by animation and isochronal activation mapping.
Analysis comprised 32 recordings from nine pigs (mean duration 5.1 ± 3.9 min). Slow-wave propagation was analyzed, and a total of 26 sources of slow-wave initiation were observed and classified as focal pacemakers (31%), sites of functional re-entry (23%) and circumferential re-entry (35%), or indeterminate sources (11%). The mean frequencies of circumferential and functional re-entry were similar (17.0 ± 0.3 vs 17.2 ± 0.4 cycle min−1; P = 0.5), and greater than that of focal pacemakers (12.7 ± 0.8 cycle min−1; P < 0.001). Velocity was anisotropic (12.9 ± 0.7 mm s−1 circumferential vs 9.0 ± 0.7 mm s−1 longitudinal; P < 0.05), contributing to the onset and maintenance of re-entry.
Conclusions & Inferences
This study has shown multiple patterns of slow-wave initiation in the jejunum of anesthetized pigs. These results constitute the first description and analysis of circumferential re-entry in the gastrointestinal tract and functional re-entry in the in vivo small intestine. Re-entry can control the direction, pattern, and frequency of slow-wave propagation, and its occurrence and functional significance merit further investigation.