title: Expression of synaptogyrin-1 in T1R2-expressing type II taste cells and type III taste cells of rat circumvallate taste buds.
abstract: Synaptogyrins are conserved components of the exocytic apparatus and function as regulators of Ca(2+)-dependent exocytosis. The synaptogyrin family comprises three isoforms: two neuronal (synaptogyrin-1 and -3) and one ubiquitous (synaptogyrin-2) form. Although the expression patterns of the exocytic proteins synaptotagmin-1, SNAP-25, synaptobrevin-2 and synaptophysin have been elucidated in taste buds, the function and expression pattern of synaptogyrin-1 in rat gustatory tissues have not been determined. Therefore, we examined the expression patterns of synaptogyrin-1 and several cell-specific markers of type II and III cells in rat gustatory tissues. Reverse transcription/polymerase chain reaction assays and immunoblot analysis revealed the expression of synaptogyrin-1 mRNA and its protein in circumvallate papillae. In fungiform, foliate and circumvallate papillae, the antibody against synaptogyrin-1 immunolabeled a subset of taste bud cells and intra- and subgemmal nerve processes. Double-labeling experiments revealed the expression of synaptogyrin-1 in most taste cells immunoreactive for aromatic L-amino acid decarboxylase and the neural cell adhesion molecule. A subset of synaptogyrin-1-immunoreactive taste cells also expressed phospholipase Cβ2, gustducin, or sweet taste receptor (T1R2). In addition, most synaptogyrin-1-immunoreactive taste cells expressed synaptobrevin-2. These results suggest that synaptogyrin-1 plays a regulatory role in transmission at the synapses of type III cells and is involved in exocytic function with synaptobrevin-2 in a subset of type II cells in rat taste buds.
authors: Division of Oral Histology and Neurobiology, Department of Health Improvement, Kyushu Dental University, Kokurakita-ku, Kitakyushu, 803-8580, Japan.
authors: Takeshi
authors: T
authors: Kotani
authors: Takashi
authors: T
authors: Toyono
authors: Yuji
authors: Y
authors: Seta
authors: Ayae
authors: A
authors: Kitou
authors: Shinji
authors: S
authors: Kataoka
authors: Kuniaki
authors: K
authors: Toyoshima
mesh_terms: D000818:Animals; D005089:Exocytosis / Q000502:physiology; D005786:Gene Expression Regulation / Q000502:physiology*; D008297:Male; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D043562:Receptors, G-Protein-Coupled / Q000096:biosynthesis*; D015398:Signal Transduction / Q000502:physiology; D062805:Synaptogyrins / Q000096:biosynthesis*; D013650:Taste Buds / Q000166:cytology / Q000378:metabolism*; D050988:Vesicle-Associated Membrane Protein 2 / Q000096:biosynthesis; D000098706:Taste Receptors, Type 2
chemical_list: D012333:RNA, Messenger; D043562:Receptors, G-Protein-Coupled; D062805:Synaptogyrins; C494706:Vamp2 protein, rat; D050988:Vesicle-Associated Membrane Protein 2; C431926:taste receptors, type 1; D000098706:Taste Receptors, Type 2