By Nicole Garneau, PhD
The best science is that which we do not expect, and the best
communication of science comes when the public is involved. So this
post is dedicated to the Blue Tongue Blog's dedicated readers. I am
so pleased that you have all shared your interest with me about the
latest study in bitter taste reception, not on the tongue-- but
unexpectedly in the lungs. There were a lot of great questions sent
my way, so I wanted to use these next 400 words or so to break down
the study which will hopefully help paint a better picture.
Overview:
1. The large airways in your lungs that branch off from the
trachea (windpipe) are called bronchi. They are made of smooth
muscle cells (cells that you don't have to think about to move,
they are also in certain organs like your heart).
2. The scientists that wrote this research paper found that
these smooth muscle cells in the bronchi have bitter taste
receptors on them that bind to certain bitter chemicals.
3. This binding of a bitter tastant to the receptor sets off a
series of signals and messages in these cells which leads to an
increase in calcium levels within them.
4. The increase in calcium opens channels in the cell membrane
which leads to hyper-polarization (making the cell more negatively
charged).
5. This hyper-polarization is the opposite of depolarization
(making cells more positively charged) that occurs with
histamine-provoked constriction of airways. So instead of
constriction, the airways actually become relaxed and open more
(bronchodilate).
Hierarchy in the body that this research
addresses:
System: Respiratory. includes the nose, throat (pharynx),
voice box (larynx), windpipe (trachea), and the lungs (all the
airways from bronchi to alveoli)
Organ: Lungs, specifically the bronchi
Cells: Smooth muscle
Protein on Cell: Bitter Taste Receptor
Signaling in Cell: bitter chemicals bind (like a lock and key)
the bitter taste receptor proteins on the surface of the cell, this
signals the cells to increase calcium, which hyper-polarizes the
cell and leads to relaxation of the muscle, thus opening the
airways.
Why should we care?
Scientists are looking to take advantage of this discovery that
stimulating bitter taste receptors in the lungs is
actually a mechanism for opening airways. The
authors of this published report discuss how this could lead to
novel treatments for asthma and chronic obstructive pulmonary
disease (COPD). Together these affect 300 million people
world-wide, and their data shows that bitter works even better than
current treatments on the market. The authors caution however that
just eating bitter food might not help (not asthma anyway, but
broccoli is good for you), instead they plan on having bitter
substances aerosolized (like in an inhaler) for people to use.
Reference Information:
The research article entitled, "Bitter taste receptors on airway
smooth muscle bronchodilate by localized calcium signaling and
reverse obstruction" was published on October 24, 2010 in
Nature Medicine, a very highly ranked science magazine/journal.
This is a peer-reviewed article, which means that it was first
submitted to other experts in that area of research to review it
and make sure the science was solid and supported the
conclusions.
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