Inhibition of gastric motility elicited by D-glucose anomers in man

Control of motor and secretory functions of the stomach by a portal glucose signal

D-glucose solution injected into the portal vein influences efferent tonic activities of the vagal nerve innervating the stomach. This suggested the existence of a neural connection between hepatic vagal branch afferents and gastric vagal efferents in the brain. Considering this observation together with findings indicating that electrical stimulation of the proximal cut end of the hepatic vagal branch changes acidity in the gastric perfusing fluid or pressure within the stomach, it has been presumed that hepatic afferent signals related to glucose may regulate the motor or secretory function of the stomach through a change in central nervous activity. Recently active interaction between the portal and medullary glucose signals in gastric function was discovered, and analysis of the characteristic features of the system is in progress.

Glucose signal in the nucleus of the vagus nerve modulates the cyclicity of gastric motility in rats

The cyclicity and intensity of gastric motility were examined following glucose injection into the nucleus of the vagus nerve (X) or into the nucleus of the solitary tract (SOL) in anesthetized rats. Enhanced gastric motility caused by insulin administration was influenced by 4 mM glucose (500 nl) injected into the X; glucose provoked a shift in the cyclicity power spectrum without any change in intensity. The peak power spectrum shifted from 4.0-5.0 cpm to 2.0-3.0 cpm, but not significant change in the cyclicity power spectrum was seen when the same dose of glucose was injected into the SOL. It was also noted that the power spectrum response to 4 mM glucose injection into the X was not modified when 4 mM glucose was injected into the SOL simultaneously. The results suggest that the medullary glucose signal in the X differentially modulates the cyclicity of gastric motility independent of the SOL.

Hepatic glucose signals vagally modulate the cyclicity of gastric motility in rats

The cyclicity and intensity of gastric motility were examined following glucose injection into the portal vein with an intragastric balloon in anesthetized rats. Enhanced gastric motility caused by insulin administration was influenced by 4 mM glucose (25 microliters) injected into the portal vein; glucose provoked a shift in the cyclicity power spectrum without any change in intensity. The peak power spectrum shifted from 4.0-5.0 cpm to 2.0-3.0 cpm. Hepatic branch vagotomy abolished the response. The results suggest that glucose signals in the hepatic vagal branch modulate the cyclicity of gastric motility.