title: Expression of amiloride-sensitive epithelial sodium channels in mouse taste cells after chorda tympani nerve crush.
abstract: Our previous electrophysiological study demonstrated that amiloride-sensitive (AS) and -insensitive (AI) components of NaCl responses recovered differentially after the mouse chorda tympani (CT) was crushed. AI responses reappeared earlier (at 3 weeks after the nerve crush) than did AS ones (at 4 weeks). This and other results suggested that two salt-responsive systems were differentially and independently reformed after nerve crush. To investigate the molecular mechanisms of formation of the salt responsive systems, we examined expression patterns of three subunits (alpha, beta and gamma) of the amiloride-sensitive epithelial Na(+) channel (ENaC) in mouse taste cells after CT nerve crush by using in situ hybridization (ISH) analysis. The results showed that all three ENaC subunits, as well as alpha-gustducin, a marker of differentiated taste cells, were expressed in a subset of taste bud cells from an early stage (1-2 weeks) after nerve crush, although these taste buds were smaller and fewer in number than for control mice. At 3 weeks, the mean number of each ENaC subunit and alpha-gustducin mRNA-positive cells per taste bud reached the control level. Also, the size of taste buds became similar to those of the control mice at this time. Our previous electrophysiological study demonstrated that at 2 weeks no significant response of the nerve to chemical stimuli was observed. Thus ENaC subunits appear to be expressed prior to the reappearance of AI and AS neural responses after CT nerve crush. These results support the view that differentiation of taste cells into AS or AI cells is initiated prior to synapse formation.
authors: Section of Oral Neuroscience, Graduate School of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
authors: Noriatsu
authors: N
authors: Shigemura
authors: Abu Ahammad S
authors: AA
authors: Islam
authors: Chiharu
authors: C
authors: Sadamitsu
authors: Ryusuke
authors: R
authors: Yoshida
authors: Keiko
authors: K
authors: Yasumatsu
authors: Yuzo
authors: Y
authors: Ninomiya
mesh_terms: D000584:Amiloride / Q000494:pharmacology*; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D002814:Chorda Tympani Nerve / Q000293:injuries / Q000502:physiology; D004594:Electrophysiology; D053503:Epithelial Sodium Channels; D017403:In Situ Hybridization / Q000379:methods; D051379:Mice; D012333:RNA, Messenger / Q000032:analysis; D015222:Sodium Channels / Q000378:metabolism*; D013268:Stimulation, Chemical; D013649:Taste / Q000187:drug effects* / Q000502:physiology; D013650:Taste Buds / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D013997:Time Factors; D015293:Transducin / Q000378:metabolism
chemical_list: D053503:Epithelial Sodium Channels; D012333:RNA, Messenger; D015222:Sodium Channels; C075192:gustducin; D000584:Amiloride; D015293:Transducin