Functional effects of cold stimulation on taste perception in humans.

Thermal modulation of signaling pathways leads to excitation of taste receptor cells, but the underlying mechanisms remain unclear. Furthermore, it has long been known that there are contrast effects in various senses. In this study, we investigated cold-taste contrast and the relationship between taste and somatosensation. We lowered intraoral temperature using cold stimulus as a pretreatment, then returned to normal temperature in 249 healthy subjects, before administering room temperature taste-stimulating solutions to investigate changes in sensitivity to the four basic tastes (Sweet, Salt, Sour, and Bitter). Statistical comparisons of taste recognition thresholds before and after cold stimulus showed increased taste sensitivity for all four basic tastes. After categorizing different levels of pre-cold stimulus taste sensitivity into groups and comparing changes in sensitivity to the four basic tastes before and after stimulus, we found that the lower the sensitivity to the four basic tastes, the greater the increase in sensitivity induced by cold stimulus. These findings suggest that taste and low temperature send afferent signals which cause interaction in the afferent pathways between the peripheral and central nervous systems. Cold stimulus may offer one possible treatment strategy for dysgeusia.