In experiments conducted by Dr. Oka, the researchers found that high salt concentrations activate previously discovered bitter- and sour-sensing cells. When one of these cell types was silenced and made incapable of sending messages to the brain, aversion to high-salt solutions was reduced, but not eliminated. When both cell types were silenced, the mammals completely lost their aversion to high-salt solutions, even showing unrestrained attraction to exceedingly salty solutions equivalent to those of seawater.
For mammals, ingesting high concentrations of seawater can lead to extreme dehydration, kidney failure, and death. With two aversion pathways, Dr. Oka said, animals have a safeguard to make sure that high salt is always aversive.
Now that all the salt pathways have been identified, Dr. Oka said, it may be possible to use that knowledge to make low concentrations of salt taste saltier, to reduce NaCl intake. It also may be possible to make the taste of KCl (potassium chloride), which has fewer long-term health effects than sodium chloride, more appealing to encourage its use as a salt substitute.
Taste Cells Will Lead to Understanding Where Sensations Are in the Brain
Though the commercial implications of the work are clear, the researchers' objective is not to find ways to alter our tastes, but to understand how we perceive the sensory world. How does the detection of high salt oncentrations on the tongue lead to a decision to turn away from a source of water? How can we tell the difference between chocolate cake and pump
|Contact: Karin Eskenazi|
Columbia University Medical Center