| Title | Water Taste Transduction Pathway Is Calcium Dependent in Drosophila. | | Author(s) | Meunier N, Marion-Poll F, Lucas P | | Institution | INRA (Institut National de Recherche Agronomique), UMR (Unité mixte de recherche) 1272 Physiologie de l'Insecte-Signalisation et Communication, F-78000 Versailles, France. | | Source | Chem Senses 2009 Apr 22. | | Abstract | In mammals, detection of osmolarity by the gustatory system was overlooked until recently. In insects, specific taste receptor neurons detect hypoosmotic stimuli and are commonly called "W" (water) cells. W cells are easy to access in vivo and represent a good model to study the transduction of hypoosmotic stimuli. Using pharmacological and genetic approaches in Drosophila, we show that tarsal W cell firing activity depends on the concentration of external calcium bathing the dendrite. This dependence was confirmed by the strong inhibition of W cell responses to hypoosmotic stimuli by lanthanum (IC(50) = 8 nM), an ion known to inhibit calcium-permeable channels. Downstream, the transduction pathway likely involves calmodulin because calmodulin antagonists such as W-7 (IC(50) = 2 muM) and fluphenazine (IC(50) = 30 muM) prevented the activation of the W cell by hypoosmotic stimuli. A protein kinase C (PKC) may also be involved as W cell responses were blocked by PKC inhibitors, chelerythrine (IC(50) = 20 muM) and staurosporine (IC(50) = 30 muM). It was also reduced when expressing an inhibitory pseudosubstrate of PKC in gustatory receptor neurons. In the rat, the transduction pathway underlying low osmolarity detection involves aquaporin and swelling-activated ion channels. Our study suggests that the transduction pathway of hypoosmotic stimuli in insects differs from mammals. | | Language | ENG | | Pub Type(s) | JOURNAL ARTICLE
| | PubMed ID | 19386695 |
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