THE NEWBORN PIGLET - A MODEL OF NEONATAL GASTROINTESTINAL MOTILITY

Small intestinal myoelectric activity has been studied extensively in adult humans and in many animal models. However, little is known about gut myoelectrical activity in newborns, a population susceptible to primary and secondary motility disorders. We report the development of a chronic neonatal piglet model for assessment of gastric and small intestinal myoelectric activity. Six piglets aged 12 to 27 days and weighing 2.3 to 4 kg underwent laparotomy and implantation of four to six bipolar serosal electrodes along the small intestine; and selectively on the gastric antrum. Myoelectric records were obtained daily after operation in awake animals using low (0.16 Hz) and high (30 Hz) frequency filters. Electrical control activity (ECA) was observed in the stomach (4 to 5 cycles per minute) and in the duodenum (14 to 15 cycles per minute) on postoperative day 1; along with random bursts of spiking activity. The migrating myoelectric complex (MMC) appeared on postoperative day 2 or 3. In piglets followed for a week or more, the MMC cycle duration and phase III duration (period of maximal spiking activity) were longer in the proximal small intestine than at the terminal ileum (80 ± 5 versus 47 ± 3 minutes and 5.1 ± 0.3 versus 3.7 ± 0.1 minutes, respectively; mean ± SEM, P < .005), suggesting that some MMCs arise spontaneously in the distal small bowel without traversing the upper intestine. The antral and duodenal ECA frequencies are similar to values reported in human adults; the MMC cycle duration is slightly shorter. The neonatal piglet model is inexpensive, reproducible, and has a similar physiology to the human gut; it may be the preferred model for studying neonatal gastrointestinal motility. © 1990.