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How Sweet It Is: Why your Taste Cells love
Sugar so much
Newswise,
March 8, 2011 — PHILADELPHIA (March 7, 2011)
– A new research study dramatically
increases knowledge of how taste cells
detect sugars, a key step in developing
strategies to limit overconsumption.
Scientists from the Monell Center and
collaborators have discovered that taste
cells have several additional sugar
detectors other than the previously known
sweet receptor.
“Detecting the sweetness of nutritive sugars is one of the most
important tasks of our taste cells,” said
senior author Robert F. Margolskee, M.D.,
Ph.D., a molecular neurobiologist at Monell.
“Many of us eat too much sugar and to help limit overconsumption, we
need to better understand how a sweet taste
cell ‘knows’ something is sweet.”;
Scientists have known for some time that the T1r2+T1r3 receptor is the
primary mechanism that allows taste cells to
detect many sweet compounds, including
sugars such as glucose and sucrose and also
artificial sweeteners, including saccharin
and aspartame.
However, some aspects of sweet taste could not be explained by the
T1r2+T1r3 receptor.
Knowing that sugar sensors in the intestine are important to how
dietary sugars are detected and absorbed,
and that metabolic sensors in the pancreas
are key to regulating blood levels of
glucose, the Monell scientists used advanced
molecular and cellular techniques to see if
these same sensors are also found in taste
cells.
The results, published in thee Proceedings
of the National Academy of Sciences USA,
indicate that several sugar sensors from
intestine and pancreas also are present in
exactly those same sweet-sensing taste cells
that have the T1r2+T1r3 sweet receptor.
“The taste system continues to amaze me at how smart it is and how it
serves to integrate taste sensation with
digestive processes,” said Margolskee.
The different sugar taste sensors may have varied roles. An intestinal
glucose sensor also found to be located in
the sweet-sensitive taste cells may provide
an explanation for another mystery of sweet
taste: why just a pinch of table salt tastes
sweet or salt added to baked goods enhances
sweet taste.
Known as SGLT1, this sensor is a transporter that moves glucose into
the sweet taste cell when sodium is present,
thus triggering the cell to register
sweetness.
The authors speculate that KATP may function in sweet taste cells to
modulate taste cell sensitivity to sugars
according to metabolic needs.
For example, this sensor may respond to hormonal signals from the gut
or pancreas to make taste cells less
responsive to sweets after we have just
eaten a sugary piece of pecan pie and do not
need additional energy..
“Sweet taste cells have turned out to be quite complex. The presence of
the KATP channel suggests that taste cells
may play a role in regulating our
sensitivity to sweet taste under different
nutritional conditions,” said first author
Karen K. Yee, Ph.D., a cellular physiologist
at Monell.
“This knowledge may someday help us understand how to limit
overconsumption of sweet foods.”;
Future studies will focus on understanding the complex connections
between taste cells and the digestive and
endocrine systems.
The Monell Chemical Senses Center is an independent nonprofit basic
research institute based in Philadelphia,
Pennsylvania.
Monell advances scientific understanding of the mechanisms and
functions of taste and smell to benefit
human health and well-being.
Using an interdisciplinary approach, scientists collaborate in the
programmatic areas of sensation and
perception; neuroscience and molecular
biology; environmental and occupational
health; nutrition and appetite; health and
well-being; development, aging and
regeneration; and chemical ecology and
communication. For more information about
Monell, visit www.monell.orgg.
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