The research, published online in PLoS ONE, reports that researchers found mice lacking the gene for the ‘taste terminator’ protein Serca3 are more sensitive to bitter tastes, and find it more aversive – possibly because they experience the taste for a longer period of time.
“Individual differences in the genes that are responsible for taste termination may explain why some people are supersensitive to certain tastes,” said Dr Liquan Huang, a molecular biologist at Monell Chemical Senses Center, USA.
“Our findings also suggest that medicines that cause patients to report unpleasant taste distortions or phantom tastes may be interfering with taste termination proteins. If so, it may be possible to develop ways to minimize these unpleasant side effects that are significant barriers to patient compliance,” he added.
The authors explained that when sweet, bitter or umami molecules interact with a receptor on the surface of a taste cell; it initiates a cascade of molecular events within the cell. One of these events involves an increase in the amount of calcium inside the cell. This ultimately causes the taste cell to send a message to the brain, however, little was known about what causes the taste cell to stop sending such signals.
Huang and his colleagues reported that the Serca3 protein turns off such tastes.
“This new knowledge helps us more fully understand how taste sensations are controlled,” said Huang. “Both the initiation and termination steps contribute to how we sense and perceive tastes.”
To demonstrate exactly how Serca3 influences taste, the researchers went on to show that mice bred to lack the Serca3 gene were more sensitive to bitter taste and also found it more unpleasant.
This response was primarily related to bitter taste. However, mice without Serca3 also responded to sweet and umami tastes as being slightly more intense as compared to the responses of normal mice.
Huang and his team said there were no reported changes for salty and sour tastes, but added that that another member of the Serca family may work in a similar way to terminate taste sensations in sweet and umami cells. As such, future studies will investigate the contribution of this component, Serca2, in regulating sweet and umami taste perception.
Source: PLoS ONE
Volume 6, Issue 8, doi: 10.1371/journal.pone.0023165
“Sarco/Endoplasmic Reticulum Ca2+-ATPases (SERCA) Contribute to GPCR-Mediated Taste Perception”
Authors: N. Iguchi, T. Ohkuri, J.P. Slack, P. Zhong, L. Huang