Salt activates different receptors depending on concentration

Do you like lots of salt? You may not be alone -- many people love salt. But, even for these salt-lovers, high concentrations of salt taste transitions from delectable to disgusting. How does this happen? We have taste receptors that recognize the sweet, savory, salty, bitter and sour tastes in the foods we ingest. This is an evolutionary adaptation that prevents us from eating potentially deadly or toxic foods. Sweet and savory foods activate one set of receptors and one pathway. On the other hand, sour and bitter foods stimulate a different set of receptors and pathways. This makes sense; different pathways informs us if a food is acceptable or potentially toxic and shouldn't be eaten.

But what about salt? A new paper published in Nature magazine, by Dr. Y. Oka and colleagues (ePub February 13, 2013, print 494: 472), provides new insight into how salty tastes transition from good to bad. At low concentrations, salt activates the savory and sweet pathways, but switches to the bitter and sour pathways at higher levels. Researchers have begun to identify specific receptors that a involved and have shown how blocking these receptors changes the reaction to salt concentrations. This research opens the door to understanding how and why we like salt at times, but not when there is too much of it.