Localization of the duodenal pacemaker and its role in the organization of duodenal myoelectric activity

Abstract

SUMMARY In two series of conscious healthy dogs, a study of duodenal electric activity was made to locate the pacemaker or site of the greatest intrinsic frequency of the pacesetter potential. In three dogs, an annular myotomy of the duodenum about 1 cm proximal (orad) to the biliary ampulla caused a reduction in the frequency of the pacesetter potential distal (caudad) to the conduction block and demonstrated that the pacemaker was not in the region of the ampulla, as had been suggested previously. Annular myotomy of the duodenum at increasing intervals distal to the pylorus in a second series of eight dogs showed that the pacemaker was present in the proximal 5 to 6 mm of duodenum. The greater frequency of the pacemaker was found to maintain constant distal conduction of the pacesetter potential. Distal conduction of the pacesetter potential was shown on occasion to be associated with the distal propagation of action potentials along the duodenum.Since the early observations of Alvarez and Mahoney (1922a and b), it has become established that a cyclically recurring rhythmic change in electric potential is propagated caudally in the longitudinal muscle layer of the small intestine of many species, including man. This has been termed the slow wave, basic electric rhythm, or pacesetter potential. According to current interpretation (Bortoff, 1965;Code, Szurszewski, Kelly, and Smith, 1968;Nelsen and Becker, 1968), the function of the pacesetter potential is to organize the motor activity of the small bowel and to define its maximal contractile frequency.Records obtained from extracellular electrodes at different levels of intact small intestine have shown that the frequency of oscillation of the pacesetter potential is greatest in the duodenum and jejunum and decreases progressively toward the terminal ileum (Armstrong, Milton, and

Mechanisms and Potential Applications of Intestinal Electrical Stimulation

“…1. Small-intestinal slow waves originate from a region in the proximal 1 cm of the duodenum and propagate as an annular wave front in an aborad direction [7]. It determines the frequency and the direction of propagation of intestinal contractions.…”

“…However, subsequent randomized controlled studies failed to produce consistent or promising results [2][3][4]. Before the 1960s there was a lack of understanding of gastrointestinal electrophysiology, which only became a topic of interest in the later 1960s and early 1970s [5][6][7][8][9]. From the 1970s to the early 1990s, Kelly and colleagues made significant contributions to the understanding of the electrical stimulation of the gut; a number of studies on intestinal electrical stimulation (IES) and its applications were reported in dogs and humans by the group [10][11][12].…”

The flow angle beneath the gastrojejunostomy predicts delayed gastric emptying in Roux-en-Y reconstruction after distal gastrectomy

“…There have been many causes proposed for the development of Roux stasis, including functional obstruction of the Roux limb, an ectopic pacemaker arising in the Roux limb that drives contractions in a reverse direction toward the stomach [11,12], and gastroparesis after vagotomy [13]. On the basis of these hypotheses, uncut Roux Y reconstruction [14] or rho-shaped Roux Y reconstruction have been proposed and found to be effective in avoiding Roux stasis [15,16].…”

Effects of Resection on the Electrical Slow Wave in Canine Jejunum

“…The frequency of the SW in the pla teau region depends upon the most proximal oscillator. The latter corresponds to what have been thought to be a specific area of the duodenum acting as a pacemaker [14,19].…”