A Pill toTreat Sugar Addiction
Drugs used to treat nicotine addiction could be used to treat sugar
addiction in animals, according toresearch from Queensland
University of Technology.
“The latest World Health Organisation igures tell us 1.9 billion
people worldwide are overweight, with 600 million considered
obese,” said Prof Selena Bartlett of QUT’s Institute of Health and
Biomedical Innovation, who is corresponding author of the study
published inPLOS ONE(http://tinyurl.com/jmolxof).
“Excess sugar consumption has been proven to contribute
directly to weight gain,” Bartlett said. “It has also been shown to
repeatedly elevate dopamine levels, which control the brain’s reward
and pleasure centres in a way that is similar to many drugs of abuse,
including tobacco, cocaine and morphine.
“After long-term consumption, this leads to the opposite: a
reduction in dopamine levels. This leads to higher consumption
of sugar to get the same level of reward.
“We have also found that as well as an increased risk of weight
gain, animals that maintain high sugar consumption and binge eating
into adulthood may also face neurological and psychiatric conse-
quences affecting mood and motivation. Our study found that Food
and Drug Administration-approved drugs like varenicline (a prescrip-
tion medication trading as Champix, which treats nicotine addic-
tion) can work the same way when it comes to sugar cravings.”PhD researcher Masroor Shariff said the study also put artiicial
sweeteners under the spotlight. “Interestingly, our study also found
that artiicial sweeteners such as saccharin could produce effects
similar to those we obtained with table sugar, highlighting the impor-
tance of re-evaluating our relationship with sweetened food per se.”
Bartlett said that varenicline acted as a neuronal nicotinic
receptor modulator (nAChR), and similar results were observed
with similar drugs such as mecamylamine and cytisine. “Like other
drugs of abuse, withdrawal from chronic sucrose exposure can
result in an imbalance in dopamine levels and be as diicult as
going ‘cold turkey’ from them,” she said.
“Further studies are required, but our results do suggest that
current FDA-approved nAChR drugs may represent a novel new
treatment strategy to tackle the obesity epidemic.”MAY 2016|| 7Subscribe online
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http://www.austscience.comWhat if snakes or whales could regrow legs, or chickens develop
teeth, or humans re-evolve tails like our primate ancestors?
Reversible evolution is possible under certain conditions – even after
many millions of years – according to a study published inEvolu-
tion(http://tinyurl.com/zkdj5hy).
An international team of scientists found that some of the
largest kangaroos ever to evolve resurrected crests on their teeth that
were present in their distant ancestors more than 20 million years
earlier. They speculate that changes in climate, habitat and diet
provided the selection pressures that resurrected these dental
features. As forests retreated towards the coastline over millions of
years, kangaroos were forced to eat more grass, and their teeth
needed to cut rather than grind their food.
Biologists have often discounted the potential for evolution to
shift into reverse, dismissing such occurrences as cases of conver-
gent evolution. However, co-author A/Prof Gavin Prideaux ofFlinders University argues that “reanimating genetically moth-
balled features may be ‘allowed’ by evolution when it aligns with
pressures that determine an animal’s ecology”.
PhD candidate Aidan Couzens found that “small changes to a
‘rule’ that determines how teeth form in the embryo have allowed
some kangaroos to partly turn back the clock on evolution. Using
these rules, we can start to predict the pathways evolution can take.
“We found that, contrary to Dollo’s law in biology, features
lost in evolution can re-evolve when evolution ‘tinkers’ with the
way features are assembled in the embryo,” Couzens says.
Prideaux says that kangaroos and wallabies have been studied
as barometers of historical climatic change in Australia. “They
have been around for at least 30 million years,” he says. “We are
discovering more about how early forms were adapted to the abun-
dant soft-leaved forest plants, and how later macropods adapted
to more arid conditions.”Evolution Goes Back to the Drawing Board
Compiled by Guy Nolchksena32/adobe