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This Article Full Text Full Text (PDF) All Versions of this Article: 296/4/G868    most recent 90511.2008v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Ma, X. Articles by Kunze, W. Search for Related Content PubMed PubMed Citation Articles by Ma, X. Articles by Kunze, W.

NEUROREGULATION AND MOTILITY

Lactobacillus reuteri ingestion prevents hyperexcitability of colonic DRG neurons induced by noxious stimuli

¹Institute of Physiology, School of Medicine, Shandong University, Shandong, China; ²Brain-Body Institute, St Joseph's Healthcare, Hamilton, Ontario; Departments of ³Medicine, ⁴Pathology and Molecular Medicine, and ⁵Psychiatry and Behavioral Neurosciences, McMaster University, Hamilton, Ontario, Canada

Submitted 25 August 2008 ; accepted in final form 14 January 2009

Lactobacillus species ingestion can decrease autonomic responses and spinal fiber discharge to nociceptive colorectal distension (CRD), even in the absence of inflammation. The present study aimed to determine whether dorsal root ganglion (DRG) somas could be a locus where the antinociceptive probiotic may have an effect. Healthy rats were fed with Lactobacillus reuteri or vehicle control for 9 days whereupon they were anesthetized, and intermittent distal colonic CRD at 80 mmHg distension was either performed for 1 h or not. The animals were immediately euthanized and patch-clamp recordings taken after isolation and overnight culture from those DRG that projected to the distal colon. CRD decreased the threshold for action potential generation and increased the number of spikes discharged during a standard depolarizing test stimulus, and this effect was blocked by prior probiotic ingestion. The increase in excitability was paralleled by an increase in DRG capacitance, which was not altered by Lactobacillus reuteri ingestion. CRD did not increase tissue weight or myeloperoxidase activity. We suggest that the effects of CRD may have been caused by activity-dependent neurotransmission between DRG somas. CRD evoked increases in action potential upstroke speed, which suggests that it may also have led to augmentation of sodium channel conductances. Probiotic ingestion may have interfered with this hypothetical mechanism since it blocked the effect of CRD on the action potential.

colorectal distension; dorsal root ganglion; probiotics; sensory neurons