Longitudinal and circumferential spread of spike bursts in canine jejunum in vivo

This study demonstrates a new method for quantitatively analyzing individual intestinal spike bursts and establishes the distribution of spike burst spread under conditions of fasting and feeding in conscious healthy dogs. The dimensions and propagation lengths of individual jejunal spike bursts were determined by studying spike burst spread within slow-wave cycles. Electromyograms were recorded simultaneously from multiple closely spaced serosal electrodes in the jejunum (4 equally distant around the circumference and 16 along the long axis at 3-cm intervals). At least 75% of the time, spike bursts involved the entire cross-sectional circumference simultaneously. Greater than 50% of spike bursts during fasting or feeding spread distally 3-30 cm. The remainder were isolated or segmental spike bursts involving < 3 cm of jejunum. The lengths of propagative spike bursts increased with the time during phase II and reached a maximum of 30-40 cm during phase III. Fed activity showed a mixture of segmental and longer propagative spike bursts that varied little with time after feeding. Propagative spike bursts > 3 cm in length produced at least 85% of the total myoelectric burst activity regardless of the state of fasting or feeding and constitute the major form of intestinal motility in the canine jejunum.