Investigation of feeding behaviour in C. elegans reveals distinct pharmacological and antibacterial effects of nicotine

Caenorhabditis elegans is an informative model to study the neural basis of feeding. A useful paradigm is one in which adult nematodes feed on a bacterial lawn which has been pre-loaded with pharmacological agents and the effect on pharyngeal pumping rate scored. A crucial aspect of this assay is th...

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Bibliographic Details
Published in:Invertebrate neuroscience 2018-12, Vol.18 (4), p.14-8, Article 14
Main Authors: Kudelska, M. M., Lewis, A., Ng, C. T., Doyle, D. A., Holden-Dye, L., O’Connor, V. M., Walker, R. J.
Format: Article
Language:English
Subjects:
Bacteria
Biomedical and Life Sciences
Biomedicine
Caenorhabditis elegans
Cell Biology
E coli
Feeding behavior
Feeding rates
Food
Food sources
Invertebrates
Investigations
Molecular Medicine
Neurobiology
Neurosciences
Nicotine
Original Article
Pharynx
Worms
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Summary:Caenorhabditis elegans is an informative model to study the neural basis of feeding. A useful paradigm is one in which adult nematodes feed on a bacterial lawn which has been pre-loaded with pharmacological agents and the effect on pharyngeal pumping rate scored. A crucial aspect of this assay is the availability of good quality bacteria to stimulate pumping to maximal levels. A potential confound is the possibility that the pharmacological agent impacts bacterial viability and indirectly influences feeding rate. Here, the actions of nicotine on pharyngeal pumping of C. elegans and on the Escherichia coli bacterial food source were investigated. Nicotine caused an immediate and concentration-dependent inhibition of C. elegans pharyngeal pumping, IC 50 4 mM (95% CI = 3.4 mM to 4.8 mM). At concentrations between 5 and 25 mM, nicotine also affected the growth and viability of E. coli lawns. To test whether this food depletion by nicotine caused the reduced pumping, we modified the experimental paradigm. We investigated pharyngeal pumping stimulated by 10 mM 5-HT, a food ‘mimic’, before testing if nicotine still inhibited this behaviour. The IC 50 for nicotine in these assays was 2.9 mM (95% CI = 3.1 mM to 5.1 mM) indicating the depletion of food lawn does not underpin the potency of nicotine at inhibiting feeding. These studies show that the inhibitory effect of nicotine on C. elegans pharyngeal pumping is mediated by a direct effect rather than by its poorly reported bactericidal actions.
ISSN:1354-2516
1439-1104
DOI:10.1007/s10158-018-0219-1