A, slow waves recorded from the greater curvature, midway and lesser curvature of the mouse gastric antrum. The resting membrane potentials were −68 mV, −65 mV and −69 mV respectively. B, the rising phases, displayed on rapid time base, of sample slow waves recorded at each location. The voltage calibration bar applies to all traces, the left-hand time calibration bar applies to A, the right-hand time calibration bar to B. The grouped observations from the experimental series are shown in C. * Experimental observations differed significantly.