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Lookup NU author(s): Alice French, Kerry Simcock, Dr Sasha Gartside, Professor Geraldine Wright
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
Serotonin (5-hydroxytryptamine, 5-HT) is involved in the regulation of feeding and digestion in many animals from worms to mammals. In insects, 5-HT functions both as a neurotransmitter and as a systemic hormone. Here we tested its role as a neurotransmitter in feeding and crop contractions and its role as a systemic hormone that affected feeding in adult foraging honeybees. We found 5-HT immunoreactive processes throughout the gut, including on the surface of the oesophagus, crop, proventriculus, and the midgut, as well as in the ventral nerve cord. mRNA transcripts for all four of the known bee 5-HT receptors (Am5-ht(1A,2 alpha,2 beta,7)) were expressed in the crop and the midgut suggesting a functional role for 5-HT in these locations. Application of a cocktail of antagonists with activity against these known receptors to the entire gut in vivo reduced the rate of spontaneous contraction in the crop and proventriculus. Although feeding with sucrose caused a small elevation of endogenous 5-HT levels in the haemolymph, injection of exogenous 5-HT directly into the abdomen of the bee to elevate 5-HT in the haemolymph did not alter food intake. However, when 5-HT was injected into directly into the brain there was a reduction in intake of carbohydrate, amino acid, or toxin-laced food solutions. Our data demonstrate that 5-HT inhibits feeding in the brain and excites muscle contractions in the gut, but general elevation of 5-HT in the bee's haemolymph does not affect food intake. (C) 2013 The Authors. Published by Elsevier Ltd. All rights reserved.
Author(s): French AS, Simcock KL, Rolke D, Gartside SE, Blenau W, Wright GA
Publication type: Article
Publication status: Published
Journal: Journal of Insect Physiology
Year: 2014
Volume: 61
Pages: 8-15
Print publication date: 01/02/2014
Online publication date: 26/12/2013
Acceptance date: 17/12/2013
Date deposited: 21/05/2014
ISSN (print): 0022-1910
ISSN (electronic): 1879-1611
Publisher: Pergamon
URL: http://dx.doi.org/10.1016/j.jinsphys.2013.12.005
DOI: 10.1016/j.jinsphys.2013.12.005
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