Intrarectal injection of glycerol induces hypersensitivity to rectal distension in healthy subjects without modifying rectal compliance.
Bouin, Mickael a; Delvaux, Michel a; Blanc, Christophe a; Lagier, Emmanuel a; Delisle, Marie-Bernadette b; Fioramonti, Jean c; Bueno, Lionel c; Frexinos, Jacques a
[Article] European Journal of Gastroenterology & Hepatology. 13(5):573-580, May 2001.

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Background: Rectal sensory thresholds are lowered in patients with irritable bowel syndrome (IBS), reflecting visceral hyperlagesia, which might be related to subclinical inflammation.

Aim: To evaluate the effects of an intraluminal injection of glycerol, a mucosal irritant, on rectal tone and perception of distension in 12 healthy subjects.

Methods: Rectal tone was evaluated with a barostat. First sensation, need to defecate and pain thresholds were evaluated during isobaric phasic distensions, before and 20 and 120 min after injection of 10 ml glycerol in the rectum.

Results: Baseline bag volume (97.9 /- 56.2 ml) significantly decreased 20 min (49.7 /- 42.2 ml;P = 0.026) and 120 min (66.5 /- 38.3 ml;P = 0.050) after injection of glycerol, indicating its hypertonic effect. The pressure defining sensory thresholds was decreased significantly 20 min after glycerol injection: first sensation, 14.6 /- 2.9 versus 18.3 /- 7.2 mmHg (P = 0.01); need to defecate, 19.6 /- 3.7 versus 26.0 /- 6.9 mmHg; pain, 23.8 /- 4.5 versus 35.6 /- 9.5 mmHg (P = 0.001). This effect was maintained for 120 min after injection of glycerol. Slopes of the compliance curves did not differ before and after injection of glycerol.

Conclusions: Intraluminal injection of glycerol significantly increases rectal tone and sensitizes healthy volunteers to rectal distension, since they show significantly lower thresholds after glycerol. This could constitute a model of visceral hypersensitivity in healthy volunteers.

(C) 2001 Lippincott Williams & Wilkins, Inc.