Visceral Sensitivity to Gastric Stimulation and its Correlation with Alterations in Gastric Emptying and Accommodation in Humans

Background: The aim of this study was to investigate the visceral sensation to gastric stimulation and its correlation with the stimulation-induced alterations in gastric accommodation and gastric emptying. Methods: The study was performed in 12 healthy human controls. Gastric stimulation was performed using bipolar electrodes attached to the mucosa of the distal stomach under endoscopy. Experiments were conducted on 3 consecutive days to investigate the effects of gastric stimulation with various parameters on visceral sensation, maximum intake of water and gastric emptying of solids. Results: 1) The stimulation energy was 265.6 ± 134.9 smA 2 for the first sensation and 2,020.0 ± 865.1 smA2 for the maximum tolerance, and there was a large variation among the subjects; 2) Gastric stimulation with stimulation energy less than 50% of that required to induce the first sensation significantly reduced the maximum intake of water and delayed gastric emptying of solids without inducing symptoms; 3) The stimulation energy of the first sensation was significantly correlated with the stimulationinduced reduction in water intake (r=−0.80, P=;0.02) and the stimulation-induced prolongation of gastric emptying (r=−0.78, P=0.003). That is, the inhibitory effects of gastric stimulation were more obvious in those subjects who were viscerally more sensitive to gastric stimulation. Conclusions: Gastric stimulation via the distal stomach reduces gastric accommodation and delays gastric emptying. These inhibitory effects are correlated with the visceral sensitivity of the individual to gastric stimulation. It is worthy to further investigate whether the outcome of the implantable gastric stimulation (IGS) therapy for obesity may be predicted from the visceral sensitivity of the patient to temporary gastric stimulation using endoscopically placed mucosal electrodes.