Non-invasive registration of the aboral and oral spreading of the gastroduodenal peristaltic activity (experimental and clinical investigations).

The electrical activity of the stomach and the upper part of the small intestine of healthy volunteers and patients with nausea and vomiting was recorded non-invasively on an original electrogastrograph. Two kinds of waves were distinguished according to their amplitude: low-amplitude waves, corresponding to the period of quiescence of migrating myoelectrical complex (MMC) and about twice higher in amplitude waves, characterising the periods of activity of MMC (peristaltic activity). There was also some difference between the low- and high-amplitude waves from the small intestine. Sequence of high-amplitude waves recorded from the stomach was followed usually by sequence of high-amplitude waves from the small intestine, presenting the aboral spreading of an activity period of MMC from the stomach to the small intestine. In some patients however, high-amplitude waves were led off first from the duodenal record and after that high-amplitude waves appeared in the gastric record. This suggests an oral spreading of the peristaltic activity (antiperistalsis). Experimental model of antiperistalsis was performed on dogs with chronically implanted electrodes on the gastric and duodenal muscle wall. Carbachol 5 micrograms/kg i.m. evoked bursts of spike potentials first with duodenal slow waves and after that with the gastric slow potentials. The antiperistaltic spreading of the spike activity in dog corresponded to the appearance of high-amplitude waves first in the record of the human small intestine, followed by sequence of high-amplitude waves in the stomach. Thus, the non-invasive recording of the electrical activity of the stomach and small intestines gives reliable information about the direction of the spreading of the peristaltic activity.