Electrical activity of canine gallbladder

Our aims were to describe the myoelectrical activity in the single very thin layer of muscle of the canine gallbladder. The study was performed on 22 freshly removed canine gallbladders. Electrical activity was studied by the single sucrose-gap method and contractility of the tissue was measured simultaneously using a force transducer. The strips (15 x 1 mm) from different regions of gallbladder (fundus, corpus, neck) were cut in longitudinal, circular and oblique axes. The sucrose-gap apparatus together with connecting tubes, solutions and electrodes were kept at 37 degrees C and the initial tension applied to the tissue was set to 1 g. In 82.7% of recordings, spontaneous myoelectrical activity consisted of regular rhythmic changes in membrane potential similar to slow waves recorded in intestinal tissue. The overall mean frequency was 11.4 +/- 5.2 (mean +/- SD) cycles per min: 11.1 +/- 4.4 cycles per min in fundus, 11.9 +/- 6.2 cycles per min in corpus and 10.8 +/- 3.8 cycles per min in the neck of the gallbladder. In 84.2% of cases electrical activity correlated with mechanical activity and preceded it. No significant differences were seen between the electrical patterns in strips with different orientations or from the different regions of the gallbladder.