Taste Enhancement by Pulsatile Stimulation Is Receptor Based But Independent of Receptor Type.

Effects of subjects' taste sensitivity (expressed as taste detection threshold), tastant quality and taste transduction mechanism on pulsation-induced taste enhancement were tested. Taste intensities of pulsatile MSG and NaCl stimuli at pulsation periods below, at and above individual taste fusion periods (TFP in seconds) were compared to taste intensities of a continuous reference of the same net tastant concentration and quality. In line with results previously reported for sucrose, pulsation-induced taste enhancement peaked around TFP for both MSG and NaCl and did not require perception of tastant pulsation. TFP and pulsation effects were independent of the taste transduction mechanism (G-protein-coupled receptor for MSG versus ion-channel for NaCl). The absence of a relation between TFP and taste sensitivity suggests that temporal gustatory resolution and taste sensitivity are not necessarily influenced by the same factors. The results support earlier findings that early stages of taste transduction are involved in pulsation-induced taste enhancement. Pulsation-induced taste enhancement is determined by the pulsation rate (i.e. TFP) which is longer for MSG than NaCl. This is probably due to the tastant-specific interaction with the receptor rather than the taste transduction mechanism (G-protein-coupled receptor versus ion-channel) involved.