title: Intrinsic nitric oxide regulates the taste response of the sugar receptor cell in the blowfly, Phormia regina.
abstract: The taste organ in insects is a hair-shaped taste sensory unit having four functionally differentiated contact chemoreceptor cells. In the blowfly, Phormia regina, cGMP has been suggested to be a second messenger for the sugar receptor cell. Generally, cGMP is produced by membranous or soluble guanylyl cyclase (sGC), which can be activated by nitric oxide (NO). In the present paper, we electrophysiologically showed that an NO scavenger, 2-phenyl-4,4,5,5-tetramethylimidazoline-3-oxide-1-oxyl (PTIO), an NO donor, 1-hydroxy-2-oxo-3-(N-methyl-3-aminopropyl)-3-methyl-1-triazene (NOC 7) or an NO synthase (NOS) inhibitor, NG-nitro-L-arginine methyl ester (L-NAME) specifically affected the response in the sugar receptor cell, but not in other receptor cells. PTIO, when introduced into the receptor cells in a sensillum aided by sodium deoxycholate (DOC, pH 7.2), depressed the response of sugar receptor cells to sucrose but did not affect those of the salt or water receptor cells. NOC 7, given extracellularly, latently induced the response of sugar receptor cells; and L-NAME, when introduced into the receptor cells, depressed the response of sugar receptor cells. The results clearly suggest that NO, which may be produced by intrinsic NOS in sugar receptor cells, participates in the transduction cascade of these cells in blowfly.
authors.affiliation: Department of Applied Physics and Chemistry, The University of Electro-Communications, Chofu, Tokyo 182-8585, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Murata
authors.forename: Masashi
authors.initials: M
authors.lastname: Mashiko
authors.forename: Mamiko
authors.initials: M
authors.lastname: Ozaki
authors.forename: Taisaku
authors.initials: T
authors.lastname: Amakawa
authors.forename: Tadashi
authors.initials: T
authors.lastname: Nakamura
mesh_terms: D000818:Animals; D002241:Carbohydrates / Q000494:pharmacology*; D002628:Chemoreceptor Cells / Q000502:physiology*; D006152:Cyclic GMP / Q000096:biosynthesis; D004175:Diptera; D004594:Electrophysiology; D006162:Guanylate Cyclase / Q000378:metabolism; D009569:Nitric Oxide / Q000096:biosynthesis / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000378:metabolism; D015290:Second Messenger Systems; D015398:Signal Transduction; D013649:Taste / Q000187:drug effects*
chemical_list: D002241:Carbohydrates; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D006162:Guanylate Cyclase; D006152:Cyclic GMP