Sensation and gas dynamics in functional gastrointestinal disorders

Abstract

Our current knowledge of motor and sensory functions in the human gut is critically reviewed, showing how the two may interact to produce symptoms in patients with functional gastrointestinal disorders. A local stimulus is necessary to activate the pathogenetic symptom generation process, and in many patients abnormal pooling of gas at various or extensive sites in the bowel and focal gut distension may provide the local stimulus, compounded by spatial summation phenomena and conscious visceral hypersensitivity. The interplay of these mechanisms results in the clinical expression of symptoms.

Figure 1

Perception of intestinal distension: effect of fat infusion (0.5 kcal/min). *p<0.05 versus saline control. Reproduced from Accarino and colleagues.⁶

Figure 2

Effect of simultaneous conditioning on perception of intestinal distension. Values are mean (SEM). *p<0.05 versus control. Reproduced from Ness and Gebhart.⁸

Figure 3

Intestinal gas dynamics and tolerance in healthy subjects and in patients with irritable bowel syndrome (IBS). Reproduced from Serra and colleagues.²⁴