Validity of long-term recordings of electrical activity of the stomach by chronically implanted monopolar suction electrodes in the conscious dog.

Twenty-four-hour changes in gastric electrical activity were recorded in conscious dogs by means of chronically implanted monopolar suction electrodes. The electrical activity consisted of an initial potential followed by a second potential with various amplitude and duration depending upon the time after feeding. Amplitude of the second potential was well correlated to magnitude of each contraction. Characteristics of the electrical activity were qualitatively similar to those obtained with the intracellular microelectrode technique. 24-hour changes in cycles of electrical activity were divided into four phases; the first phase (lasting for 2--4 hours after feeding) characterized by a significant decrease in the cycle, the second phase (until 6--8 hours after feeding) in which the cycle gradually increased, the third phase (10--16 hours after feeding), and the last phase (lasting to the next meal), showing a marked variation in the cycle. These changes occurred irrespectively at the time of feeding and were consistent day after day as long as the animals were held on a constant feeding schedule. The recording method was suitable for recording gastric electrical activity which would provide more precise informations occurring in the intracellular electrical activity of the stomach in a long period of time under a physiological condition.