Breaking News on Sweet Taste Perception

[angevin]

MONELL CHEMICAL SENSES CENTER

ADVANCING DISCOVERY IN TASTE AND SMELL

Media contact: Leslie Stein, 267.519.4707 or stein@monell.org

How Sweet It Is: Why Your Taste Cells Love Sugar So Much

Multiple taste cell sensors contribute to detecting sugars

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. For example, although the receptor contains two

subunits that must join together for it to work properly,

Margolskee’s team had previously found that mice engineered to be

missing the T1r3 subunit were still able to taste glucose and other

sugars normally.

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 the 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.

In pancreas, the sugar sensor known as the KATP channel, monitors

glucose levels and triggers insulin release when they rise. 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.

Also contributing to the study were Sunil Sukumaran, Ph.D. and Ramana

Kotha of Monell and Timothy Gilbertson, Ph.D. of Utah State

University.

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.org.

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Edited March 8, 2011 by angevin (log)

[angevin]

It's easy to begin speculating on the implications of this research.

"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. "

For instance, this could be the reason that has kids perceiving bitter to a greater extent than adults; kids need calories and the bitter tempers the sweet taste of foods like chocolate.

Edited March 8, 2011 by angevin (log)