Inhibitory effects of gastric electrical stimulation on ghrelin-induced excitatory effects on gastric motility and food intake in dogs

Objective. To investigate the effects of ghrelin on food intake, gastric motility and whether gastric electrical stimulation (GES) is capable of reversing these effects of ghrelin in dogs. Material and methods. Seven healthy dogs were equipped with a gastric cannula and electrodes for the measurement of antral motility and gastric myoelectrical activity (GMA). Both food intake and gastric motility studies were performed in three sessions (control, ghrelin, 20 mg and ghrelin plus GES) in randomized order, respectively. After a 28-h fast, the animals were provided with unlimited solid food for 1.5 h, 30 min after saline or ghrelin injection. Recordings of antral contractions and GMA in each session were recorded for 30 min at baseline and 45 min after ghrelin/saline injection in the fasting state. GES was performed throughout the experiment initiated 30 min prior to the injection. Results. 1) Ghrelin significantly increased food intake from 475.6 +/- 75.5 g in the controls to 535.9 +/- 90.3 g with ghrelin (p=0.04); this excitatory effect was reversed by GES. 2) Ghrelin significantly increased the motility index from 8.6 +/- 1.6 in the controls to 16.1 +/- 2.4 with ghrelin (p=0.01) and this effect was also reversed by GES. 3). There were no effects of ghrelin on GMA. Conclusions. Ghrelin induces antral contractions and increases food intake. GES is capable of blocking these excitatory effects of ghrelin. These findings suggest that GES may inhibit the resistant effect of ghrelin on weight loss.