Abstract
A subset of rodent taste cells is known to generate action potentials in response to taste stimuli. Some of these cells express molecular markers for cell types that may transmit taste information to gustatory nerve fibers. The present study investigated the possible role of spiking taste cells on gustatory sensory transmission. Taste responses of spiking taste cells in isolated mouse fungiform taste buds were examined and compared them with those of chorda tympani (CT) nerve fibers innervating fungiform papillae. Response selectivity among four taste stimuli (NaCl, HCl, saccharin, quinine) was evaluated as the entropy value of the breadth of responsiveness of each taste cells and fibers. The mean entropy value was not significantly different between fungiform taste cells and CT fibers, indicating that the range of responsiveness of spiking taste cells may be close to that of innervating axons in mice. The cluster dendrogram obtained from data on response patterns of individual mouse fungiform taste cells to four taste stimuli resembled that of CT nerves. Proportions of taste cells predominantly responding to one of four taste stimuli were similar to those of nerve fibers. These results indicate corresponding groupings of taste cells and nerve fibers in mice. This consistency in response characteristics of taste cells and nerve fibers suggest that taste cells generating action potentials may play a major role on transmission of taste information to gustatory nerve fibers. Supported by JSPS Grants-in-Aid 15209061 (YN). [Jpn J Physiol 55 Suppl:S167 (2005)]
