title: Expression of equilibrative nucleoside transporter 1 in rat circumvallate papillae.
abstract: In gustatory function, communication between four types taste buds cells plays crucial roles. ATP is one of the intercellular signaling molecules in taste buds, and the extracellular ATP fate is regulated by its cellular clearance, but there is little information on it. Therefore, we examined the expression profiles of nucleoside transporters (NTs) as a clearance system for ATP metabolite adenosine in rat circumvallate papillae (CP) by RT-PCR, real-time PCR and immunohistochemistry. Among NTs, mRNA for Ent1 was expressed by the CP, and significantly was greater in the CP as compared with non-CP. ENT1 immunoreactivity was detected in PLC-β2-positive type II (71.0±8.5%), chromogranin-A-positive type III (64.9±7.4%), and SNAP25-positive type III (77.0±10.4%) taste cells, but not in NTPDase2-positive type I ones. These results indicate that ENT1-expressing type II and III taste cells might comprise an adenosine clearance system in taste buds of the CP. ENT1 expression in taste cells is important for elucidation of complicated taste signaling.
authors.affiliation: Department of Environmental Biochemistry, Kyoto Pharmaceutical University, Misasagi, Kyoto 607-8414, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Nishida
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Kitada
authors.forename: Junki
authors.initials: J
authors.lastname: Kato
authors.forename: Yukari
authors.initials: Y
authors.lastname: Dohi
authors.forename: Kazuki
authors.initials: K
authors.lastname: Nagasawa
mesh_terms: D000818:Animals; D033721:Equilibrative Nucleoside Transporter 1 / Q000235:genetics / Q000378:metabolism*; D033722:Equilibrative-Nucleoside Transporter 2 / Q000235:genetics / Q000378:metabolism; D008297:Male; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013650:Taste Buds / Q000378:metabolism*
chemical_list: D033721:Equilibrative Nucleoside Transporter 1; D033722:Equilibrative-Nucleoside Transporter 2; D026901:Membrane Transport Proteins; D020033:Protein Isoforms; C065171:cif nucleoside transporter