PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

Ketamine acts as antidepressant by boosting serotonin

PET molecular imaging of the brain reveals that ketamine may act as an antidepressant by boosting serotonin activity in brain areas involved in motivation

2014-01-07
(Press-News.org) Contact information: Juliette Savin
pr@riken.jp
81-080-889-52136
RIKEN
Ketamine acts as antidepressant by boosting serotonin PET molecular imaging of the brain reveals that ketamine may act as an antidepressant by boosting serotonin activity in brain areas involved in motivation Ketamine is a potent anesthetic employed in human and veterinary medicine, and sometimes used illegally as a recreational drug. The drug is also a promising candidate for the fast treatment of depression in patients who do not respond to other medications. New research from the RIKEN Center for Life Science Technologies in Japan demonstrates using PET imaging studies on macaque monkeys that ketamine increases the activity of serotoninergic neurons in the brain areas regulating motivation. The researchers conclude that ketamine's action on serotonin, often dubbed the "feel-good neurotransmitter", may explain its antidepressant action in humans.

The study, published today in the journal Translational Psychiatry demonstrates that Positron Emission Tomography (PET) molecular imaging studies may be useful in the diagnosis of major depressive disorder in humans, as well as the development of new antidepressants.

Ketamine has recently been shown to have an antidepressant action with short onset and long-term duration in patients suffering from treatment-resistant major depressive disorder, who do not respond to standard medications such as serotonin reuptake inhibitors, monoamine oxidase inhibitors and tricyclic antidepressants. However, the mechanisms underlying ketamine's action on the depressive brain have remained unclear.

To understand the effects of ketamine on the serotonergic system in the brain, Dr Hajime Yamanaka and Dr Hirotaka Onoe, who has pioneered PET imaging on conscious non-human primates, together with an international team, performed a PET study on rhesus monkeys.

The team performed PET imaging studies on four rhesus monkeys with two tracer molecules related to serotonin (5-HT) that bind highly selectively to the serotonin 1B receptor 5-HT1B and the serotonin transporter SERT.

From the analysis of the 3 dimensional images generated by the PET scans, the researchers could infer that ketamine induces an increase in the binding of serotonin to its receptor 5-HT1B in the nucleus accumbens and the ventral pallidum, but a decrease in binding to its transporter SERT in these brain regions. The nucleus accumbens and the ventral pallidum are brain regions associated with motivation and both have been shown to be involved in depression.

In addition, the researchers demonstrate that treatment with NBQX, a drug known to block the anti-depressive effect of ketamine in rodents by selectively blocking the glutamate AMPA receptor, cancels the action of ketamine on 5-HT1B but not on SERT binding.

Taken together, these findings indicate that ketamine may act as an antidepressant by increasing the expression of postsynaptic 5-HT1B receptors, and that this process is mediated by the glutamate AMPA receptor.

### For more information please contact: Juliette Savin
RIKEN
Tel: +81-(0)48-462-1225
Email: pr@riken.jp

Reference:

Yamanaka et al. "A possible mechanism of the nucleus accumbens and ventral pallidum 5-HT1B receptors underlying the antidepressant action of ketamine: a PET study with macaques." Translational Psychiatry, 2013 DOI: DOI: 10.1038/tp.2013.112

About RIKEN RIKEN is Japan's flagship research institute for basic and applied research. Over 2500 papers by RIKEN researchers are published every year in reputable scientific and technology journals, covering topics ranging across a broad spectrum of disciplines including physics, chemistry, biology, medical science and engineering. RIKEN's advanced research environment and strong emphasis on interdisciplinary collaboration and globalization has earned an unparalleled reputation for scientific excellence in Japan and around the world.

About the Center for Life Science technologies The RIKEN Center for Life Science Technologies aims to develop key technologies for breakthroughs in the medical and pharmaceutical applications of life science as well as conduct ground-breaking research and development for the next-generation life sciences.


ELSE PRESS RELEASES FROM THIS DATE:

U of Maryland undergraduates discover rare eclipsing double asteroid

2014-01-07
U of Maryland undergraduates discover rare eclipsing double asteroid Fewer than 100 such asteroids have been found in main asteroid belt COLLEGE PARK, MD – Students in a University of Maryland undergraduate astronomy class have made a rare discovery that wowed professional ...

Ancient sharks reared young in prehistoric river-delta nursery

2014-01-07
Ancient sharks reared young in prehistoric river-delta nursery ANN ARBOR—Like salmon in reverse, long-snouted Bandringa sharks migrated downstream from freshwater swamps to a tropical coastline to spawn 310 million years ago, leaving behind fossil evidence of one of ...

How you practice matters for learning a skill quickly

2014-01-07
How you practice matters for learning a skill quickly Practice alone doesn't make perfect, but learning can be optimized if you practice in the right way, according to new research based on online gaming data from more than 850,000 people. The ...

Ants shape their thoraces to match the tasks they perform

2014-01-07
Ants shape their thoraces to match the tasks they perform This news release is available in Portuguese. It was now discovered that the specialization of queen and worker ants goes beyond the presence or absence of wings. In a study published ...

Racism may accelerate aging in African-American men

2014-01-07
Racism may accelerate aging in African-American men UMD-led study is first to link racism-related factors and cellular age A new study reveals that racism may impact aging at the cellular level. Researchers found signs of accelerated aging in African American men, ages reporting ...

NYSCF scientists make living brain cells from Alzheimer's patients biobanked brain tissue

2014-01-07
NYSCF scientists make living brain cells from Alzheimer's patients biobanked brain tissue New study shows ability to make living human cells from biobanked brain tissue NEW YORK, NY (January 7, 2014) – Scientists at The New York Stem Cell Foundation (NYSCF) Research ...

Some brain regions retain enhanced ability to make new connections

2014-01-07
Some brain regions retain enhanced ability to make new connections In adults, some brain regions retain a "childlike" ability to establish new connections, potentially contributing to our ability to learn new skills and form new memories as we age, ...

Several forms of vitamin E protect against memory disorders

2014-01-07
Several forms of vitamin E protect against memory disorders Elderly people with high serum vitamin E levels are less likely to suffer from memory disorders than their peers with lower levels, according to a study published recently in Experimental ...

Patterns of social interaction remain consistent over time

2014-01-07
Patterns of social interaction remain consistent over time The research was conducted by researchers form Aalto University and University of Oxford, and was published in Proceedings of the National Academy of Sciences of the United States of America (PNAS) recently. "We ...

The power of packaging in consumer choices

2014-01-07
The power of packaging in consumer choices Researchers from the University of Miami and California Institute of Technology show how the brain considers both visual cues and taste preferences when making everyday food choices CORAL GABLES, FL (January 6, 2014) — ...

LAST 30 PRESS RELEASES:

Older teens who start vaping post-high school risk rapid progress to frequent use

Corpse flowers are threatened by spotty recordkeeping

Riding the AI wave toward rapid, precise ocean simulations

Are lifetimes of big appliances really shrinking?

Pink skies

Monkeys are world’s best yodellers - new research

Key differences between visual- and memory-led Alzheimer’s discovered

% weight loss targets in obesity management – is this the wrong objective?

An app can change how you see yourself at work

NYC speed cameras take six months to change driver behavior, effects vary by neighborhood, new study reveals

New research shows that propaganda is on the rise in China

Even the richest Americans face shorter lifespans than their European counterparts, study finds

Novel genes linked to rare childhood diarrhea

New computer model reveals how Bronze Age Scandinavians could have crossed the sea

Novel point-of-care technology delivers accurate HIV results in minutes

Researchers reveal key brain differences to explain why Ritalin helps improve focus in some more than others

Study finds nearly five-fold increase in hospitalizations for common cause of stroke

Study reveals how alcohol abuse damages cognition

Medicinal cannabis is linked to long-term benefits in health-related quality of life

Microplastics detected in cat placentas and fetuses during early pregnancy

Ancient amphibians as big as alligators died in mass mortality event in Triassic Wyoming

Scientists uncover the first clear evidence of air sacs in the fossilized bones of alvarezsaurian dinosaurs: the "hollow bones" which help modern day birds to fly

Alcohol makes male flies sexy

TB patients globally often incur "catastrophic costs" of up to $11,329 USD, despite many countries offering free treatment, with predominant drivers of cost being hospitalization and loss of income

Study links teen girls’ screen time to sleep disruptions and depression

Scientists unveil starfish-inspired wearable tech for heart monitoring

Footprints reveal prehistoric Scottish lagoons were stomping grounds for giant Jurassic dinosaurs

AI effectively predicts dementia risk in American Indian/Alaska Native elders

First guideline on newborn screening for cystic fibrosis calls for changes in practice to improve outcomes

Existing international law can help secure peace and security in outer space, study shows

[Press-News.org] Ketamine acts as antidepressant by boosting serotonin
PET molecular imaging of the brain reveals that ketamine may act as an antidepressant by boosting serotonin activity in brain areas involved in motivation