The Effects of Transections on the Basic Electrical Rhythm in the Canine Jejunum

Abstract

The basic electrical rhythm (BER) was studied in situ in the jejunum in 14 anaesthetized mongrel dogs by the mean of six monopolar electrodes. The BER frequency was measured in the intact intestine and after proximal and distal transections of the gut 5 cm apart from the electrodes. No significant differences were found between the BER frequencies recorded by each electrode, demonstrating the existence of a frequency plateau which remained after each transection. In the intact intestine the frequency in the plateau was 13.2+0.3 cpm². After the proximal transection, this frequency dropped to 12.0+0.4 cpm (p < 0.05) and, after the distal transection, it dropped to 10.9+0.4 cpm (p < 0.05). This last frequency change shows the influence of the distal intestine on the electrical behaviour of the jejunum.

Effects of Resection on the Electrical Slow Wave in Canine Jejunum

“…The surgical transection of the intestine results in a fall of the SW frequency recorded from the intestine distal to the site of transec tion [5,17,20,22]. If successive cuts are per formed, each of them leads to a further fall of the SW frequency in the intestine distal to each transection site [22] and in the intestinal segments thereafter isolated [17], The SW is spontaneously generated by the smooth mus cle cells themselves [25,29], The transection experiments, by showing that the SW fre quency is greater at a site in the intact intes tine than in isolated segments removed from the same site demonstrate clearly that, in the intact intestine, the SW of a population of cells is influenced by the SW of neighbouring populations.…”

“…If successive cuts are per formed, each of them leads to a further fall of the SW frequency in the intestine distal to each transection site [22] and in the intestinal segments thereafter isolated [17], The SW is spontaneously generated by the smooth mus cle cells themselves [25,29], The transection experiments, by showing that the SW fre quency is greater at a site in the intact intes tine than in isolated segments removed from the same site demonstrate clearly that, in the intact intestine, the SW of a population of cells is influenced by the SW of neighbouring populations. This phenomenon is best ex plained by the concept that the small bowel behaves like a chain of coupled relaxation oscillators with caudally decreasing intrinsic frequencies [5,20,22], A rigid coupling leads to a phase lock of the oscillators which there fore beat at the same common frequency.…”