Cellular identification of water gustatory receptor neurons and their central projection pattern in Drosophila

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 103; no. 4; pp. 1094 - 1099
• Main Authors: Inoshita, T, Tanimura, T
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 24.01.2006; National Acad Sciences
• Subjects: Animals; Axons; Biological Sciences; Brain - metabolism; Cell Nucleus - metabolism; Chemoreceptor Cells; Drosophila; Drosophila melanogaster; Drosophila Proteins; Electrophysiology; Enhancer Elements, Genetic; Female; Genes, Insect; Green Fluorescent Proteins - metabolism; Gustatory perception; gustatory receptor neurons; Insects; Male; Nerve Tissue - metabolism; Neurology; Neurons; Neurons - metabolism; Neurons, Afferent - chemistry; neurophysiology; Papillae; Peripheral Nervous System - metabolism; Receptors; Sense Organs; Sensilla; sensory neurons; Sensory perception; Shaker Superfamily of Potassium Channels - chemistry; subesophageal ganglia; Sugars; Taste; Taste Buds - metabolism; Time Factors; Toxins; Transgenes; Water; Water - metabolism; water receptor neurons
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.0502376103

Water perception is important for insects, because they are particularly vulnerable to water loss because their body size is small. In Drosophila, gustatory receptor neurons are located at the base of the taste sensilla on the labellum, tarsi, and wing margins. One of the gustatory receptor neurons in typical sensilla is known to respond to water. To reveal the neural mechanisms of water perception in Drosophila, it is necessary to identify water receptor neurons and their projection patterns. We used a Gal4 enhancer trap strain in which GAL4 is expressed in a single gustatory receptor neuron in each sensillum on the labellum. We investigated the function of these neurons by expressing the upstream activating sequence transgenes, shibire(ts1), tetanus toxin light chain, or diphtheria toxin A chain. Results from the proboscis extension reflex test and electrophysiological recordings indicated that the GAL4-expressing neurons respond to water. We show here that the water receptor neurons project to a specific region in the subesophageal ganglion, thus revealing the water taste sensory map in Drosophila.