PACING OF THE GASTRIC ELECTRICAL ACTIVITIES BFEORE AND AFTER VAGOTOMY

Pacing of the gastric electrical activities was carried out in six normal dogs and three gastric vagotomized dogs in the conscious state . The gastric wall was stimulated by a single rectangular current of 1 to 30V amplitude with 5 to 100 msec. duration. A premature electrical activity could be evoked by giving the electrical stimulation through a stimulating electrode in an optimal period of one cycle in the basic electrical rhythm. Pacing could be established by repeating the stimulation with the optimal frequencies. The evoked electrical activities propagated both aborad and orad directions. The evoked activities were propagated aboradly immediatly after stimulation, while the orad propagation occured following a certain period of delay . Maximum driven frequencies (MDF) obtained from antral stimulation in the normal fasting dogs were 6.8-9.5 cycles/min. MDF were varied in each dog. The values of MDF in the fasting state were higher than those after feeding, and gastric antral stimulation generated higher MDF than gastric corpus stimulation . When the gastric electrical activities were paced in higher frequencies, the phase lag among them were increased. After vagotomy, the manner of entrainment of the gastric electrical activities was different from that of prevagotomy. Chiefly in fasting, a phenomena was observed , in which despite of ceasing the stimulation, the electrically evoked activities were remained in the same frequencies for a few minutes as if the stimulation was kept on. The MDF obtained from antral stimulation in the fasting state after vagotomy were higher than those before vagotomy.