title: Taste responsiveness of fungiform taste cells with action potentials.
abstract: It is known that a subset of taste cells generate action potentials in response to taste stimuli. However, responsiveness of these cells to particular tastants remains unknown. In the present study, by using a newly developed extracellular recording technique, we recorded action potentials from the basolateral membrane of single receptor cells in response to taste stimuli applied apically to taste buds isolated from mouse fungiform papillae. By this method, we examined taste-cell responses to stimuli representing the four basic taste qualities (NaCl, Na saccharin, HCl, and quinine-HCl). Of 72 cells responding to taste stimuli, 48 (67%) responded to one, 22 (30%) to two, and 2 (3%) to three of four taste stimuli. The entropy value presenting the breadth of responsiveness was 0.158 +/- 0.234 (mean +/- SD), which was close to that for the nerve fibers (0.183 +/- 0.262). In addition, the proportion of taste cells predominantly sensitive to each of the four taste stimuli, and the grouping of taste cells based on hierarchical cluster analysis, were comparable with those of chorda tympani (CT) fibers. The occurrence of each class of taste cells with different taste responsiveness to the four taste stimuli was not significantly different from that of CT fibers except for classes with broad taste responsiveness. These results suggest that information derived from taste cells generating action potentials may provide the major component of taste information that is transmitted to gustatory nerve fibers.
authors.affiliation: Section of Oral Neuroscience, Graduate School of Dental Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
authors.forename: Ryusuke
authors.initials: R
authors.lastname: Yoshida
authors.forename: Noriatsu
authors.initials: N
authors.lastname: Shigemura
authors.forename: Keisuke
authors.initials: K
authors.lastname: Sanematsu
authors.forename: Keiko
authors.initials: K
authors.lastname: Yasumatsu
authors.forename: Satoru
authors.initials: S
authors.lastname: Ishizuka
authors.forename: Yuzo
authors.initials: Y
authors.lastname: Ninomiya
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000465:Algorithms; D000818:Animals; D002452:Cell Count; D002814:Chorda Tympani Nerve / Q000166:cytology / Q000502:physiology; D003627:Data Interpretation, Statistical; D004594:Electrophysiology; D019277:Entropy; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009412:Nerve Fibers / Q000502:physiology; D018408:Patch-Clamp Techniques; D013268:Stimulation, Chemical; D013649:Taste / Q000502:physiology*; D013650:Taste Buds / Q000166:cytology / Q000502:physiology*