Genetically-increased taste cell population with Gα-gustducin-coupled sweet receptors is associated with increase of gurmarin-sensitive taste nerve fibers in mice

摘要

BackgroundThe peptide gurmarin is a selective sweet response inhibitor for rodents. In mice, gurmarin sensitivity differs among strains with gurmarin-sensitive C57BL and gurmarin-poorly-sensitive BALB strains. In C57BL mice, sweet-responsive fibers of the chorda tympani (CT) nerve can be divided into two distinct populations, gurmarin-sensitive (GS) and gurmarin-insensitive (GI) types, suggesting the existence of two distinct reception pathways for sweet taste responses. By using the dpa congenic strain (dpa CG) whose genetic background is identical to BALB except that the gene(s) controlling gurmarin sensitivity are derived from C57BL, we previously found that genetically-elevated gurmarin sensitivity in dpa CG mice, confirmed by using behavioral response and whole CT nerve response analyses, was linked to a greater taste cell population co-expressing sweet taste receptors and a Gα protein, Gα-gustducin. However, the formation of neural pathways from the increased taste cell population to nerve fibers has not yet been examined.