Intracellular free calcium concentration in human taste bud cells increases in response to taste stimuli.

We examined changes of intracellular free calcium concentration [Ca2+]i elicited by taste stimuli of sucrose, denatonium and NaCl in the taste buds of seven human fungiform papillae. In one taste bud we observed an increase in [Ca2+]i induced by only NaCl. In another bud an increase of [Ca2+]i in response to both NaCl and sucrose was found. The Ca2+ responses to NaCl and sucrose occurred in differential areas within the one taste bud. In the other five fungiform papillae [Ca2+]i was not changed by the taste stimuli. These results suggest that an increase of [Ca2+]i participates in taste transduction mechanisms for sucrose and NaCl, and that taste cells in one taste bud may respond to differential stimuli.