Gastric electrical stimulation inhibits postprandial antral tone partially via nitrergic pathway in conscious dogs

Abstract

Gastric electrical stimulation (GES) has recently been explored as a therapeutic option for gastrointestinal motility disorders or obesity. The mechanism behind it is not fully elucidated. The aims of this study were to assess the effects of GES with different parameters on antral tone and to explore the involvement of the nitrergic pathway. Eight dogs equipped with a gastric cannula and one pair of serosal electrodes in the greater curvature 4 cm above the pylorus were studied on separate days. The study was composed of seven randomized sessions in the fed state [control, GES with different parameters, and GES plus neuronal nitric oxide synthase (nNOS) inhibitor]. Each session included three consecutive 30-min periods (baseline, GES, and recovery). GES was performed with long pulses or pulse trains. The antral volume was measured using an intragastric balloon connected with a barostat device. Behaviors of the dogs during each stimulation period were also noted. We found that 1) postprandial antral tone was reduced with GES with all tested parameter settings, reflected as a significant and substantial increase in antral volume ranging from 179 to 309%; 2) the inhibitory effect of GES on antral tone was partially blocked (decreased by 39.5%) with an nNOS inhibitor; and 3) mild symptoms were induced with GES and found to be correlated with the GES-induced increase in antral volume. We conclude that retrograde GES with long pulses or pulse trains inhibits antral tone, and this inhibitory effect is partially mediated via the nitrergic pathway. These results suggest that retrograde GES may have a therapeutic potential for obesity.

Effects and Mechanisms of Electrical Stimulation of the Stomach, Duodenum, Ileum, and Colon on Gastric Tone in Dogs

“…The involvement of the nitrergic pathway was previously reported with GES, DES, and CES [13,[25][26][27] from our group. One canine study reported that the inhibitory effect of GES on gastric tone was partially mediated by the nitrergic pathway [25], and another study found that the inhibitory effect of DES on gastric tone was also mediated through the nitrergic pathway in dogs [13].…”

“…From these previous studies, it is known that electrical stimulation with long pulses is more potent at altering gastric motility, such as gastric tone. The involvement of the nitrergic pathway with GES, DES, and CES was previously investigated in our group and the inhibitory effect of long-pulse GES and DES on gastric tone was reported to be mediated through the nitrergic pathway in dogs [13,[25][26][27] . However, it is still not clear whether the effect of ileal electrical stimulation (IES) on gastric tone is mediated through the nitrergic pathway or not.…”

Systematic review: applications and future of gastric electrical stimulation

“…Gastric electrical stimulation with long pulses is capable of altering gastric (both fundic and antral) tone substantially in dogs. [46][47][48] With low stimulation energy, GES with long pulses may change the gastric tone slightly, which may be beneficial to patients with an impaired gastric relaxation. With high stimulation energy, GES could substantially inhibit the gastric tone and result in a substantial distention of the stomach, which may actually lead to an early satiety and be applied for treating obesity rather than gastroparesis.…”

Retrograde gastric electrical stimulation suppresses calorie intake in obese subjects

“…IGS and iGES both activate satiety neurons located in the hypothalamus through vagal and spinal afferent pathways, and alter central nervous system and gastrointestinal hormone levels. Study has shown that RGES has stronger effects on mechanical, neuronal, and hormonal pathways as compared to IGS (11)(12)(13).…”