title: Functional expression of ionotropic purinergic receptors on mouse taste bud cells.
abstract: Neurotransmitter receptors on taste bud cells (TBCs) and taste nerve fibres are likely to contribute to taste transduction by mediating the interaction among TBCs and that between TBCs and taste nerve fibres. We investigated the functional expression of P2 receptor subtypes on TBCs of mouse fungiform papillae. Electrophysiological studies showed that 100 microm ATP applied to their basolateral membranes either depolarized or hyperpolarized a few cells per taste bud. Ca(2+) imaging showed that similarly applied 1 mum ATP, 30 microm BzATP (a P2X(7) agonist), or 1 microm 2MeSATP (a P2Y(1) and P2Y(11) agonist) increased intracellular Ca(2+) concentration, but 100 microm UTP (a P2Y(2) and P2Y(4) agonist) and alpha,beta-meATP (a P2X agonist except for P2X(2), P2X(4) and P2X(7)) did not. RT-PCR suggested the expression of P2X(2), P2X(4), P2X(7), P2Y(1), P2Y(13) and P2Y(14) among the seven P2X subtypes and seven P2Y subtypes examined. Immunohistostaining confirmed the expression of P2X(2). The exposure of the basolateral membranes to 3 mm ATP for 30 min caused the uptake of Lucifer Yellow CH in a few TBCs per taste bud. This was antagonized by 100 microm PPADS (a non-selective P2 blocker) and 1 microm KN-62 (a P2X(7) blocker). These results showed for the first time the functional expression of P2X(2) and P2X(7) on TBCs. The roles of P2 receptor subtypes in the taste transduction, and the renewal of TBCs, are discussed.
authors: Kyushu Institute of Technology, Hibikino 2-4, Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, Kitakyushu 808-0196, Japan.
authors: Ryotaro
authors: R
authors: Hayato
authors: Yoshitaka
authors: Y
authors: Ohtubo
authors: Kiyonori
authors: K
authors: Yoshii
mesh_terms: D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / Q000031:analogs & derivatives / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D020013:Calcium Signaling / Q000187:drug effects; D005456:Fluorescent Dyes; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D007546:Isoquinolines; D008564:Membrane Potentials; D051379:Mice; D008856:Microscopy, Fluorescence / Q000379:methods; D018408:Patch-Clamp Techniques; D011732:Pyridoxal Phosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D018048:Receptors, Purinergic P2 / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D058476:Receptors, Purinergic P2X2; D058486:Receptors, Purinergic P2X7; D058472:Receptors, Purinergic P2Y1; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013649:Taste; D013650:Taste Buds / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D013873:Thionucleotides / Q000494:pharmacology; D013997:Time Factors; D014544:Uridine Triphosphate / Q000378:metabolism
chemical_list: D005456:Fluorescent Dyes; D007546:Isoquinolines; C546402:P2rx2 protein, mouse; C546469:P2rx7 protein, mouse; C546383:P2ry1 protein, mouse; D018048:Receptors, Purinergic P2; D058476:Receptors, Purinergic P2X2; D058486:Receptors, Purinergic P2X7; D058472:Receptors, Purinergic P2Y1; D013873:Thionucleotides; C077792:pyridoxal phosphate-6-azophenyl-2',4'-disulfonic acid; C033901:3'-O-(4-benzoyl)benzoyladenosine 5'-triphosphate; D011732:Pyridoxal Phosphate; C063302:KN 62; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D000255:Adenosine Triphosphate; C017475:lucifer yellow; C002630:alpha,beta-methyleneadenosine 5'-triphosphate; D014544:Uridine Triphosphate; C008501:2-methylthio-ATP
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