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.