Article

Lactobacillus reuteri ingestion and IK(Ca) channel blockade have similar effects on rat colon motility and myenteric neurons

Department of Medicine, McMaster University, Hamilton, ON, Canada.
Neurogastroenterology and Motility (Impact Factor: 3.59). 09/2009; 22(1):98-107, e33. DOI: 10.1111/j.1365-2982.2009.01384.x
Source: PubMed

ABSTRACT

We have previously shown that ingestion of Lactobacillus reuteri may modulate colonic enteric neuron activity but with unknown effects on colon motility. The aim of the present report was to elucidate the neuronal mechanisms of action of the probiotic by comparing the effects on motility of L. reuteri ingestion with blockade of a specific ionic current in enteric neurons.
We have used intraluminal pressure recordings from ex vivo rat colon segments and whole cell patch clamp recordings from neurons of rat longitudinal muscle myenteric plexus preparations to investigate the effects of L. reuteri and TRAM-34 on colon motility and neurophysiology. The effects of daily feeding of 10(9) L. reuteri bacteria or acute application of TRAM-34 on threshold fluid filling pressure or pulse pressure was measured.
Lactobacillus reuteri increased intraluminal fluid filling pressure thresholds for evoking pressure pulses by 51% from 0.47 +/- 0.17 hPa; the probiotic also decreased the pulse pressure amplitudes, but not frequency, by 18% from 3.91 +/- 0.52 hPa. The intermediate conductance calcium-dependent potassium (IK(Ca)) channel blocker TRAM-34 (3 micromol L(-1)) increased filling threshold pressure by 43% from 0.52 +/- 0.22 hPa and reduced pulse pressure amplitude by 40% from 2.63 +/- 1.11 hPa; contraction frequency was unaltered. TRAM-34 (3 micromol L(-1)) reduced membrane polarization, leak conductance and the slow afterhyperpolarization current in 16/16 myenteric rat colon AH cells but 19/19 S cells were unaffected.
The present results are consistent with L. reuteri enhancing tonic inhibition of colon contractile activity by acting via the IK(Ca) channel current in AH cells.

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    • "The unbalanced sex distribution allowed us to verify that the probiotic efficacy is not invalidated by gender differences. The exact mechanisms by which L. reuteri might exert its beneficial action on GI has yet to be elucidated, but it seems mediated by activity on colonic intrinsic sensory neurons with an improvement in gut motility, function and effects on visceral pain (Kunze et al., 2009;Wang et al., 2010). This action may be particularly important in the developing GI system of the neonates. "
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    Full-text · Article · Mar 2014 · International Journal of Food Sciences and Nutrition
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    • "Maternal separation in rats, a model for early life stress, reduces the similarity of the GM significantly [45]. Administration of Lactobacillus spp. to rats may reduce visceral pain sensitivity [98] [99]. "
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    ABSTRACT: The gut microbiota (GM) composition and its impact on animal experiments has become currently dramatically relevant in our days: (1) recent progress in metagenomic technologies, (2) the availability of large scale quantitative analyses to characterize even subtle phenotypes, (3) the limited diversity of laboratory rodent GM due to strict barriers at laboratory animal vendors, and (4) the availability of up to 300.000 different transgenic mouse strains from different sources displaying a huge variety in their GM composition. In this review the GM is described as a variable in animal experiments which need to be reduced for scientific as well as ethical reasons, and strategies how to implement this in routine diagnostic procedures are proposed. We conclude that we have both enough information available to state that the GM has an essential impact on animal models, as well as the methods available to start dealing with these impacts.
    Full-text · Article · Mar 2012 · Comparative immunology, microbiology and infectious diseases
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    • "It has been shown that Lactobacillus reuteri ingestion consistently alters the motility of colon segments in an ex vivo organ bath recording setup. The effect is a decrease in the amplitudes of contractions at constant luminal filling preasure, and an increase in the threshold luminal pressure required to evoke rhythmic contractions (Wang et al., 2010). On the other hand, an in vivo study showed that administration of probiotics induces increased colonic propulsive contractions and defecation rate in pigs (Ohashi et al., 2001). "
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    ABSTRACT: Twenty one male Wistar albino rats each weighing approximately 280 g were used in this study. Animals were divided into three groups. The first group (n = 7) consisted of sham controls, in the second (n = 7), rats were administrated 0.1 g/1 ml/galactooligosaccharide by by oral gavage for 4 weeks. In the third group (n = 7), rats were administrated 10 9 CFU/1ml/day Bifidobacterium lactis by oral gavage for 4 weeks. After 4 weeks, rats were sacrified; ileum and proximal colon segments were removed. The spontaneous contractions of ileum and proximal colon were evaluated by using organ bath. It has been detected that both prebiotics and probiotics increased intestinal motility. While probiotics have effects on both ileum and proximal colon, prebiotics seem to be effective in colon. All data are expressed as mean ± SEM (standard error of mean). Statistical comparisons between groups were performed using general linear models of analysis of variance (ANOVA) followed by the Turkey test.
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