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This Article Full Text Full Text (PDF) All Versions of this Article: 93/3/334    most recent expphysiol.2007.039180v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Lammers, W. J. E. P. Articles by Stephen, B. Search for Related Content PubMed PubMed Citation Articles by Lammers, W. J. E. P. Articles by Stephen, B.

¹ Department of Physiology, Faculty of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates

The pattern of propagation of slow waves in the small intestine is not clear. Specifically, it is not known whether propagation is determined by a single dominant ICC-MP (Interstitial cells of Cajal located in the Myenteric Plexus) pacemaker unit or whether there are multiple active pacemakers. To determine this pattern of propagation, waveforms were recorded simultaneously from 240 electrodes distributed along the whole length of the intact isolated feline small intestine. After the experiments, the propagation patterns of successive individual slow waves were analysed. In the intact small intestine, there was only a single slow wave pacemaker unit active, and this was located at or 6–10 cm from the pyloric junction. From this site, slow waves propagated in the aboral direction at gradually decreasing velocities. The majority of slow waves (73%) reached the ileocaecal junction while the remaining waves were blocked. Ligation of the intestine at one to four locations led to: (a) decrease in the distal frequencies; (b) disappearance of distal propagation blocks; (c) increase in velocities; (d) emergence of multiple and unstable pacemaker sites; and (e) propagation from these sites in the aboral and oral directions. In conclusion, in the quiescent feline small intestine a single pacemaker unit dominates the organ, with occasional propagation blocks of the slow waves, thereby producing the well-known frequency gradient.

(Received 24 June 2007; accepted after revision 17 December 2007; first published online 21 December 2007)
Corresponding author W. J. E. P. Lammers: Department of Physiology, Faculty of Medicine and Health Sciences, PO Box 17666, Al Ain, United Arab Emirates. Email: wlammers{at}smoothmap.org