Gastrointestinal myoelectric activity disturbances in gastric ulcer disease in rats and dogs.

Electrical spiking activity of the antrum, duodenum, and jejunum was recorded from chronically implanted electrodes in rats and dogs. Gastric ulceration was induced by physical restraint in rats and by indomethacin treatment in dogs. In rats, restraint caused a 30% reduction of intestinal slow-wave frequency. After restraint the basal electrical rhythm (BER) returned to normal but in ulcerated rats the amplitude of spike potentials decreased and the migrating myoelectric complexes (MMC) of fasting were abolished by a continuous irregular spiking activity. In dogs, the amplitude of spiking activity progressively declined after the 6th day of indomethacin treatment. The frquency of the canine MMCs during the interdigestive state decreased from 0.6 to 0.2 per hour in ulceraed dog. The duration of the postprandial disorganization increased from 8 to 20 hr. It is concluded that, independent of the ulcerogenic factors, gastric ulceration induced both a reduction of the amplitude of the intestinal spiking activity and disruption of the MMCs.