This may turn out to be important
as it lifts levels of all three neurotransmitters and does not otherwise pear
to be mucking with biochemistry as far as is presently known. Everyone is going to want this stuff
available.
The boundary between a perfect
memory and most memory is far closer that anyone assumes, thus anything that
gives it a measured boost is likely to be far more valuable than expected.
The human trials will have to be
conducted and toxicity needs to also be understood but at this point it appears
rather safe. It may even make a great
cheese.
By Darren
Quick
23:08 July 1, 2012
Rapamycin, a bacterial product first discovered in a soil sample from
Easter Island, has been found to enhance learning and memory in young and old
mice alike (Image: Shutterstock)
Rapamycin, a bacterial product first discovered in a soil sample from
Easter Island – also known as Rapa Nui, hence the name – is an immunosuppressant
drug used to prevent rejection in organ transplants that has now been found to
enhance learning and memory in young and old mice alike. Researchers at the School of Medicine
at The University of Texas (UT) Health
Science Center
San Antonio
made the discovery while looking for a way to prevent the decline in cognitive
skills that comes with age.
The researchers added rapamycin, which is also known as sirolimus and
is marketed by Pfizer under the trade name Rapamune, to the diet of healthy
mice throughout their lifespan and found the drug's effects held true for mice
of all ages.
“We made the young ones learn, and remember what they learned, better
than what is normal,” said Veronica Galvan, Ph.D., assistant professor of
physiology at the Barshop Institute for Longevity and Aging Studies, part of
the UT Health Science Center. “Among the older mice, the ones fed with a diet
including rapamycin actually showed an improvement, negating the normal decline
that you see in these functions with age.”
Dr. Galvan said the drug also lowered anxiety and depressive-like
behavior in mice – both factors that impair human cognitive performance.
As burrowers that prefer tunnels with walls, mice are uncomfortable in
open spaces. So, to observe the behavior of the mice, the researchers used an
elevated maze that led to an open catwalk. Compared to those with a regular
diet, they observed that mice fed with a diet containing rapamycin spent
significantly more time exploring the catwalk, indicating they experienced less
anxiety.
A second test to measure the depressive-like behavior of the rodents
took advantage of the fact that mice don’t like to be held by their tails. As
this is the way they are moved from cage to cage, they inevitably struggle to
find a way out, and how much and how often they struggle can provide a measure
of the motivation to get out of an uncomfortable situation.
Some mice barely struggle to get free, but if an antidepressant is
administered they struggle a lot more. This behavior is very sensitive to the
action of antidepressants and is a reliable measure of whether a drug is acting
like an antidepressant, Dr. Galvan said.
“We found rapamycin acts like an antidepressant – it increases the time
the mice are trying to get out of the situation,” she said. “They don’t give
up; they struggle more.”
The team says the reduction in anxiety and depressive-like behavior in
the mice treated with rapamycin was observed in all ages tested, from four
months of age, which equates to college age in human years, to 12 months old,
which is equivalent to middle age, right through to 25 months of age, which
equates to advanced age in humans.
The researchers also measured levels of serotonin, dopamine and
norepinephrine, which are “happy, feel-good” neurotransmitters. All three of
these chemical messengers in the brain were significantly elevated in the mice
treated with rapamycin, which Dr. Galvan says may explain rapamycin’s effects.
The team’s study was published last week in the journal Neuroscience.
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