A team of scientists from the
University of Queensland have found the expression of twelve taste receptors
particularly those that respond to bitter compounds in human hearts.
During a study to understand how
the heart grows under normal conditions as well as under disease conditions
scientists were able to find the presence of smell and taste receptors
Research team leader and Head of
the School Professor Walter Thomas said "This is quite remarkable, as the
human genome only has 25 of these bitter taste receptors, and we wanted to find
out why half of them were located in the heart,"
During the activation of one of
the taste receptors with a chemical that taste as bitter the contractile
function of the heart was almost completely inhibited. The phenomenon was
originally discovered by former UQ PhD student Dr Simon Foster. The findings of
Dr Foster are published in The Journal of the Federation of American Societies
for Experimental Biology.
Receptors in Humans
Taste receptors facilitate the
sensation of taste. Taste receptors are located in the taste buds of the
papillae. Human tongue has 2,000-8,000 taste buds. Bitter, sour, salty, sweet,
and umami are the five elements of taste perception.
of Bitter Taste Receptors
The existence of bitter taste receptors
family is traced back to more than ten years ago by I. Lush, a geneticist. Lush
studied the mouse strain differences in bitter taste avoidance.
The process of local duplication
and differentiation of the original bitterness gene could have resulted in a
cluster of bitterness-tasting genes, said Lush. Researcher Adler and his team
found region of human chromosome 5 linked to perception of a bitter compound
6-n-propyl-2-thiouracil (PROP). The TAS2R proteins function as bitter taste
After a heart attack or high
, human heart undergoes compensatory growth in order to
maintain blood circulation around the body. The end outcome of this
compensatory growth is heart failure. One of the major cause of death in
Australia is heart failure.
The research study conducted with
rodent heart cells focused at the genes that are regulated in the heart during
the compensatory growth time.
Scientists found the presence of
smell and taste receptors which are normally present in the nose and mouth also
can be present on the human heart. "Through the collaborations with the
Prince Charles Hospital in Brisbane the project progressed from animal studies
to human investigations", said Professor Thomas.
Researchers by using heart tissue
from humans undergoing heart surgery
replicated the rodent laboratory
experiments and discovered the presence of taste receptors in the human heart.
heart beats 100,000 times in a day and about 35 million times in one
largest artery in the body is the aorta almost the diameter of a garden
hose. Heart capillaries are so small that it takes ten of them to equal
the thickness of a human hair.
body has about 5.6 litres of blood and human heart pumps about 1 million
barrels of blood during an average lifetime
Dr Foster had been awarded a two-year Danish Council
for Independent Research Medical Sciences postdoctoral fellowship of $A356,000,
said Professor Thomas.