Long-pulse gastric electrical stimulation at tachygastrial frequency reduces food intake by inhibiting proximal gastric tone

Objective. To investigate the effects of long pulse gastric electrical stimulation (GES) at a tachygastrial frequency on food intake, gastric tone and gastric myoelectrical activity (GMA). Material and methods. Of twelve dogs implanted with electrodes and a gastric cannula, 6 underwent truncal vagotomy. Stimulus consisted of long pulses with a frequency of 9 cycles/min. Experiment one was performed in all dogs to test for food intake with or without GES. Experiment two on six normal dogs consisted of baseline, GES and recovery periods. Gastric volume and GMA were recorded. Results. 1) GES reduced food intake in both normal (398.5±111.7 g versus 573.0±97.9 g; p<0.02) and vagotomized dogs (170.6±100.4 g versus 401.0±97.3 g; p<0.05). 2) Gastric volume was increased with stimulation from 168.4±17.7 ml to 301.1±34.1 ml (p<0.02 ANOVA) and maintained at 271.8±27.6 ml. 3) The percentages of normal slow waves before, during and after GES were 83.3±4.6%, 38.0±3.5% and 61.0±12.5%, respectively (p=0.02 ANOVA). Conclusion. Long-pulse GES at tachygastrial frequency substantially reduces food intake, and is not mediated by the vagal pathway but attributed to relaxation of the stomach and impairment of intrinsic GMA.