Modification of small bowel mechanosensitivity by intestinal fat.
BACKGROUND
Lipids may exacerbate symptoms induced by gut stimuli.


OBJECTIVE
To determine the mechanism whereby fat exerts this effect.


METHODS
Twenty four healthy subjects were studied during fasting.


METHODS
We measured perception (0-6 scale) in response to jejunal balloon distension and transmucosal electrical nerve stimulation; phasic stimuli (one minute) were randomly applied at five minute intervals during intestinal infusion (2 ml/min) of saline and then Intralipid 2 kcal/min (high fat; n=8 subjects), Intralipid 0.5 kcal/min (low fat; n=8), or saline (n=8).


RESULTS
Intestinal lipids increased the perception of jejunal distension regardless of concentration (by 53% with high fat, 49% with low fat, and 17% with saline; p<0.05 for both fat loads). This effect could not be attributed to changes in intestinal compliance as intraballoon pressures remained unchanged during lipid infusion (2% change; NS). Sensitisation induced by lipids seemed to be specifically related to intestinal mechanoreceptors because electrical stimulation, which non-specifically activates gut afferents, was perceived equally during saline and lipid administration (10%, 11%, and 15% change during high fat, low fat, and saline, respectively; NS).


CONCLUSIONS
Physiological amounts of lipids heighten intestinal sensitivity by modulating intestinal mechanoreceptor response.
Accarino
A M
AM
Digestive System Research Unit, Hospital General Vall d'Hebron, Autonomous University of Barcelona, Barcelona, Spain.
Azpiroz
F
F
Malagelada
J R
JR
D000328:Adult; D002404:Catheterization; D004041:Dietary Fats / Q000494:pharmacology*; D005215:Fasting / Q000502:physiology; D005260:Female; D006801:Humans; D007583:Jejunum / Q000187:drug effects / Q000502:physiology*; D008297:Male; D008465:Mechanoreceptors / Q000187:drug effects / Q000502:physiology*; D010147:Pain Measurement; D010465:Perception / Q000502:physiology; D012965:Sodium Chloride / Q000494:pharmacology; D018709:Statistics, Nonparametric; D004561:Transcutaneous Electric Nerve Stimulation
D004041:Dietary Fats; D012965:Sodium Chloride