Lactobacillus reuteri enhances excitability of colonic AH neurons by inhibiting calcium‐dependent potassium channel opening

• Published in: Journal of cellular and molecular medicine 2009-08, Vol.13 (8b), p.2261-2270
• Main Authors: Kunze, Wolfgang A., Mao, Yu‐Kang, Wang, Bingxian, Huizinga, Jan D., Ma, Xuelian, Forsythe, Paul, Bienenstock, John
• Format: Article
• Language: English
• Subjects: Action potential; Afterhyperpolarization; Animals; Antagonists; Bacteria; Calcium; calcium‐dependent potassium channel; Channel gating; Channel opening; Clotrimazole; Colon; Colon - cytology; Colon - physiology; Depolarization; Diarrhea; Enteric nervous system; Excitability; Experiments; Gastric motility; Genotype & phenotype; Inflammatory bowel diseases; Intestinal motility; Intestine; ion channel; Ion Channel Gating - physiology; Ions; Irritable bowel syndrome; Laboratories; Lactobacillus reuteri - physiology; Male; Molecular Target; Motility; Mucosa; Neurogenesis; Neurons; Neurons - physiology; Organisms; Pain; Pain perception; Permeability; Phenotypes; Physiology; Potassium; Potassium channels (calcium-gated); Potassium Channels - physiology; Potassium Channels, Calcium-Activated - antagonists & inhibitors; Potassium Channels, Calcium-Activated - physiology; Probiotics; rat; Rats; Rats, Sprague-Dawley; Sensory neurons; Travellers
• ISSN: 1582-1838; 1582-4934
• DOI: 10.1111/j.1582-4934.2009.00686.x

Probiotics are live non‐pathogenic commensal organisms that exert therapeutic effects in travellers’ diarrhea, irritable bowel syndrome and inflammatory bowel disease. Little is known about mechanisms of action of commensal bacteria on intestinal motility and motility‐induced pain. It has been proposed that probiotics affect intestinal nerve function, but direct evidence for this has thus far been lacking. We hypothesized that probiotic effects might be mediated by actions on colonic intrinsic sensory neurons. We first determined whether sensory neurons were present in rat colon by their responses to chemical mucosal stimulation and identified them in terms of physiological phenotype and soma morphotype. Enteric neuron excitability and ion channel activity were measured using patch clamp recordings. We fed 109Lactobacillus reuteri (LR) or vehicle control to rats for 9 days. LR ingestion increased excitability (threshold for evoking action potentials) and number of action potentials per depolarizing pulse, decreased calcium‐dependent potassium channel (IKCa) opening and decreased the slow afterhyperpolarization (sAHP) in sensory AH neurons, similar to the IKCa antagonists Tram‐34 and clotrimazole. LR did not affect threshold for action potential generation in S neurons. Our results demonstrate that LR targets an ion channel in enteric sensory nerves through which LR may affect gut motility and pain perception.