Reduced mechanosensitivity of duodenal vagal afferent neurons after an acute switch from milk-based to plant-based diets in anaesthetized pigs.
Acute changes in diet composition and/or origin alter gastric emptying and gastrointestinal motility. One of the hypotheses explaining these alterations involves changes in the sensitivity of duodenal vagal sensory neurons. The aim of this study was to evaluate the characteristics of multimodal duodenal vagal sensory neurons in 20 pigs feed either with milk-based or plant-based diets of identical caloric content. Twenty duodenal vagal afferents were recorded in anesthetized animal from the cervical vagus using the single fiber method. 10 pigs were fed with a milk-based diet (MD) for one month while the diet of the 10 other pigs was changed for plant-based diet (PD) the day preceding the recording session. The behavior of the receptors was tested in basal resting conditions and after challenges with duodenal intralipid and close intra-arterial injection of CCK, 5-HT or capsaicin with and without isovolumetric duodenal distensions at 20, 40 and 60 mmHg. All receptors were slowly adapting C type fiber with a receptor field located 6-7 cm distal to the pylorus. The rate of discharge during distension (20, 40 and 60 mmHg) combined with duodenal intralipid was significantly larger for MD compared with PD. Similarly, the rate of discharge observed during distensions performed with CCK and with 5-HT were greater for MD compared with PD while CCK and 5-HT without distension were equally stimulating for MD and PD. No significant difference was found between groups during capsaicin infusion irrespective of the stimulating pressure. In conclusion, a switch to plant-based diet, when compared to a milk-based diet, results in an overall decrease in mechanical sensitivity of duodenal neurons during lipid, 5HT and CCK challenges, but not in basal conditions or after capsaicin. This reduced sensitivity to distension may explain the diet-induced alteration of gastric emptying that is controlled primarily through a vago-vagal reflex.
Bligny
D
D
Department of Food Intake Control, UMR SENAH, 35590 Saint-Gilles, France.
Blat
S
S
Chauvin
A
A
Guérin
S
S
Malbert
C-H
CH
D000200:Action Potentials; D000768:Anesthesia, General; D000818:Animals; D002211:Capsaicin / Q000008:administration & dosage; D002766:Cholecystokinin / Q000008:administration & dosage; D003187:Compliance; D004386:Duodenum / Q000187:drug effects / Q000294:innervation* / Q000378:metabolism*; D005260:Female; D005746:Gastric Emptying; D007269:Injections, Intra-Arterial; D008055:Lipids / Q000008:administration & dosage; D040542:Mechanotransduction, Cellular / Q000187:drug effects; D008894:Milk Proteins / Q000378:metabolism*; D009475:Neurons, Afferent / Q000187:drug effects / Q000502:physiology*; D010812:Physical Stimulation; D014674:Plant Proteins, Dietary / Q000378:metabolism*; D011312:Pressure; D012018:Reflex; D012701:Serotonin / Q000008:administration & dosage; D013268:Stimulation, Chemical; D013552:Swine; D014630:Vagus Nerve / Q000187:drug effects / Q000502:physiology*
D008055:Lipids; D008894:Milk Proteins; D014674:Plant Proteins, Dietary; D012701:Serotonin; D002766:Cholecystokinin; D002211:Capsaicin