A biogenic amine and a neuropeptide act identically: tyramine signals through calcium in drosophila tubule stellate cells

Cabrero, P. , Richmond, L., Nitabach, M., Davies, S.A. and Dow, J.A.T. (2013) A biogenic amine and a neuropeptide act identically: tyramine signals through calcium in drosophila tubule stellate cells. Proceedings of the Royal Society of London Series B: Biological Sciences, 280(1757), Art. 20122943. (doi:10.1098/rspb.2012.2943)

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Abstract

Insect osmoregulation is subject to highly sophisticated endocrine control. In Drosophila, both Drosophila kinin and tyramine act on the Malpighian (renal) tubule stellate cell to activate chloride shunt conductance, and so increase the fluid production rate. Drosophila kinin is known to act through intracellular calcium, but the mode of action of tyramine is not known. Here, we used a transgenically encoded GFP::apoaequorin translational fusion, targeted to either principal or stellate cells under GAL4/UAS control, to demonstrate that tyramine indeed acts to raise calcium in stellate, but not principal cells. Furthermore, the EC(50) tyramine concentration for half-maximal activation of the intracellular calcium signal is the same as that calculated from previously published data on tyramine-induced increase in chloride flux. In addition, tyramine signalling to calcium is markedly reduced in mutants of NorpA (a phospholipase C) and itpr, the inositol trisphosphate receptor gene, which we have previously shown to be necessary for Drosophila kinin signalling. Therefore, tyramine and Drosophila kinin signals converge on phospholipase C, and thence on intracellular calcium; and both act to increase chloride shunt conductance by signalling through itpr. To test this model, we co-applied tyramine and Drosophila kinin, and showed that the calcium signals were neither additive nor synergistic. The two signalling pathways thus represent parallel, independent mechanisms for distinct tissues (nervous and epithelial) to control the same aspect of renal function.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Cabrero, Mr Pablo and Dow, Professor Julian and Davies, Professor Shireen and Richmond, Dr Laura
Authors: Cabrero, P., Richmond, L., Nitabach, M., Davies, S.A., and Dow, J.A.T.
College/School:College of Medical Veterinary and Life Sciences > Institute of Molecular Cell and Systems Biology
College of Medical Veterinary and Life Sciences > Institute of Biodiversity Animal Health and Comparative Medicine
Journal Name:Proceedings of the Royal Society of London Series B: Biological Sciences
Publisher:The Royal Society
ISSN:0962-8452
ISSN (Online):1471-2954
Published Online:27 February 2013
Copyright Holders:Copyright © 2013 The Authors
First Published:First published in Proceedings of the Royal Society of London Series B: Biological Sciences 280(1757):20122943
Publisher Policy:Reproduced under a Creative Commons License

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