Variations of the gastric electrical activity in man produced by administration of pentagastrin and by introduction of water or liquid nutritive substance into the stomach

Circadian patterns of gastric electrical and mechanical activity in dogs

Gastric motor function assessment, in humans and animals, is typically performed for short recording periods. The aim of this article was to monitor gastric electrical and motor activity in the antrum and fundus simultaneously, for long periods, using a new implantable system. Ten dogs were implanted with fundic and antral electrodes for assessment of impedance and electrical activity. Dogs were studied while in cages, for periods of 22-26 h. From late evening and until feeding on the next day, slow wave (SW) rhythm demonstrated a distinct pattern of intermittent pauses (mean duration = 22.8 +/-4.1 s) that delineated groups of SW's. Phasic increases in fundic tone were seen mostly in association with SW pauses, and were highly correlated with antral contractions, R(2) = 0.652, P < 0.05. The SW rate (events per minute) in the postprandial period, fasting and night time was 4.2 +/- 0.2, 5 +/- 0.2 and 4.7 +/- 0.3, respectively, P < 0.05 postprandial vs other periods. Antral and fundic mechanical activities were highly correlated during fasting, particularly at night. This novel method of prolonged gastric recording provides valuable data on the mechanical and electrical activity of the stomach, not feasible by current methods of recording. During fasting, fundic and antral motor activities are highly correlated and are associated with periodic pauses in electrical activity.

Association between gastric electromechanical activity and satiation in dogs

OBJECTIVE

The objective of this study was to validate the use of impedance for measurement of antral contractions and to determine the relationship between food-induced changes in gastric motility and satiation.

RESEARCH METHODS AND PROCEDURES

In Experiment 1, three dogs were implanted with an antral strain gauge and bipolar electrodes for measurement of local tissue impedance. Impedance and strain gauge recordings were obtained simultaneously during antral contractions to correlate impedance changes with contractile events. In Experiment 2, seven dogs were implanted with two pairs of gastric electrodes for simultaneous recording of slow wave activity and impedance. The changes in the rate of slow waves and of antral contractions assessed by impedance during food intake were characterized.

RESULTS

Variations in strain gauge amplitude were highly correlated with changes in antral impedance (R2: 0.70 to 0.82, p < 0.05). In Experiment 2, slow wave rate was significantly reduced after food intake and reached a nadir at satiation (5.0 +/- 0.3 vs. 3.8 +/- 0.5 events/min, p < 0.001). Likewise, the amplitude of antral contractions assessed by variations in impedance was significantly increased after food intake, peaking at satiation (5.3 +/- 1.4 vs. 12.2 +/- 4.3 Ohms, p < 0.01).

DISCUSSION

Measurement of impedance is a reliable tool for assessing gastric contractility. Food ingestion significantly reduces slow wave rate and enhances antral contractions. Peak changes in these two variables occur at the time of satiation. Electrical measurements of both slow waves and impedance may be used to estimate gastric motility and satiation.

Electrical spike potentials of the small bowel: a comparative study of recordings obtained from muscular implanted and intraluminal suction electrodes

Electrical spike potentials from the canine duodenum have been recorded from intramuscular implanted and intraluminal suction electrodes. There was a significantly greater amplitude of the spike potentials recorded from implanted electrodes, otherwise the potentials were identical in number, duration and time of onset. Thus spike potentials recorded from suction electrodes, as used in clinical motility studies, accurately represent the event within the muscular layer.