Valium-like drugs use the same potentially addictive "reward pathways" in the brain as heroin and cannabis, scientists said on Wednesday, findings which may help in the search for non-addictive alternative anxiety drugs.
Researchers from Switzerland and the United States found that so-called benzodiazepine drugs, such as Ativan, Xanax and Valium, exert a calming effect by boosting action of a neurotransmitter called gamma-aminobutyric acid (GABA) in the same way as addictive drugs like opioids and cannabinoids.

This in turn activates the gratification hormone, dopamine, in the brain, the scientists said, showing that the same brain "reward pathways" are used by both types of drugs.

The findings may help in developing a next generation of non-addictive benzodiazepines, they wrote in the journal Nature.

Roche's drug Valium, known generically as diazepam, is the best known of the benzodiazepine class of drugs, which have dominated the anxiety medicine market since the 1960s.

It and Ativan were among a host of other prescription drugs found in the blood of American pop star Michael Jackson when he died in June last year.

The study found that benzodiazepines seemed to work by binding to a particular part of the GABA, which the researchers named as the alpha1 sub-unit of the GABA type A receptor.

The findings show that developing similar benzodiazepines that bind to a different part may offer the same drug benefits without the addictive side effects, they said.

A study published earlier this month found that people with higher levels of dopamine in the brain tend to be more prone to addictive behavior.

Drug companies have been trying for some time to develop next-generation benzodiazepines by tweaking their chemical make-up to deliver a more selective effect that avoids unwanted side effects, but it has so far proved an uphill struggle.

German scientists conducting early research into a new compound said last year they thought they may have found a better anxiety drug which could counteract panic attacks without the side effects of existing drugs.

In 2003 Merck & Co abandoned work on another potential anxiety drug known as GABA Alpha 2/Alpha 3, after mid-stage clinical trial results were disappointing.

Valium-like drugs use the same potentially addictive "reward pathways" in the brain as heroin and cannabis, scientists said on Wednesday, findings which may help in the search for non-addictive alternative anxiety drugs.
Researchers from Switzerland and the United States found that so-called benzodiazepine drugs, such as Ativan, Xanax and Valium, exert a calming effect by boosting action of a neurotransmitter called gamma-aminobutyric acid (GABA) in the same way as addictive drugs like opioids and cannabinoids.

This in turn activates the gratification hormone, dopamine, in the brain, the scientists said, showing that the same brain "reward pathways" are used by both types of drugs.

The findings may help in developing a next generation of non-addictive benzodiazepines, they wrote in the journal Nature.

Roche's drug Valium, known generically as diazepam, is the best known of the benzodiazepine class of drugs, which have dominated the anxiety medicine market since the 1960s.

It and Ativan were among a host of other prescription drugs found in the blood of American pop star Michael Jackson when he died in June last year.

The study found that benzodiazepines seemed to work by binding to a particular part of the GABA, which the researchers named as the alpha1 sub-unit of the GABA type A receptor.

The findings show that developing similar benzodiazepines that bind to a different part may offer the same drug benefits without the addictive side effects, they said.

A study published earlier this month found that people with higher levels of dopamine in the brain tend to be more prone to addictive behavior.

Drug companies have been trying for some time to develop next-generation benzodiazepines by tweaking their chemical make-up to deliver a more selective effect that avoids unwanted side effects, but it has so far proved an uphill struggle.

German scientists conducting early research into a new compound said last year they thought they may have found a better anxiety drug which could counteract panic attacks without the side effects of existing drugs.

In 2003 Merck & Co abandoned work on another potential anxiety drug known as GABA Alpha 2/Alpha 3, after mid-stage clinical trial results were disappointing.

Interfering in mosquitoes' sex lives could help halt the spread of malaria, British scientists said on Tuesday.A study on the species of mosquito mainly responsible for malaria transmission in Africa, Anopheles gambiae, showed that because these mosquitoes mate only once in their lives, meddling with that process could dramatically cut their numbers.
Researchers from Imperial College London found that a "mating plug" used by male mosquitoes to ensure their sperm stays in the right place in the female is essential for her to be able to fertilize eggs during her lifetime.
Without the mating plug, sperm is not stored properly and fertilization is disrupted, they wrote in the study in the journal PLoS Biology.
"The plug plays an important role in allowing the female to successfully store sperm in the correct way inside her, and as such is vital for successful reproduction," Flaminia Catteruccia of Imperial's life sciences department wrote.
"Removing or interfering with the mating plug renders copulation ineffective. This discovery could be used to develop new ways of controlling populations of Anopheles gambiae mosquitoes, to limit the spread of malaria."
Around 40 percent of the world's population is at risk of malaria, a potentially deadly disease which is transmitted via mosquito bites.
It kills more than a million people worldwide each year and children account for about 90 percent of the deaths in the worst affected areas of sub-Saharan Africa and parts of Asia.
Catteruccia's team analyzed the composition of the male mosquito's mating plug and found it is formed when an enzyme called transglutaminase interacts with proteins in the male mosquito's seminal fluid. This interaction causes the fluid to clot into a gelatinous solid mass, known as the mating plug.
When the researchers knocked out the enzyme in male mosquitoes in the lab, the plug could not form, meaning reproduction failed when they mated.
If this process could be developed for use in the field, perhaps in a spray form like an insecticide, it could "effectively induce sterility in female mosquitoes in the wild," Catteruccia wrote, offering potential as "one more weapon in the arsenal against malaria."
Health experts want more effort to go in to a multi-pronged approach to fighting malaria, combining prevention measures like insecticides and bed nets with improved access to the best drug treatments in highest risk areas.
The World Health Organization said last week that increased funding was starting to pay off in the battle against the killer disease.

A Russian Soyuz spacecraft with three astronauts on board blasted off from Kazakhstan on Monday to join a U.S.-Russian duo manning the International Space Station (ISS).Russian Oleg Kotov, NASA's Timothy Creamer and Japan's Soichi Noguchi lifted off from Russia's Baikonur cosmodrome in Kazakhstan as planned, at 0052 Moscow time (4:52 p.m. EST on Sunday).
"Attention, spaceship Soyuz TMA-17, successfully reached its designated orbit," said an announcer at mission control to the applause of control workers and officials from the Russian, U.S. and Japanese space agencies.
After the first nine, most critical minutes into the flight, the Soyuz reached its targeted orbit at altitudes varying between 200 km and 242 km (125-151 miles) above earth.
TOY MASCOT
The space trio smiled and wove hands during the lift-off. A fluffy toy mascot hanging on a string over their heads started floating around the cabin as they reached weightlessness.
"Now it's all normal, they have started their work in orbit. At 0800 (5 a.m. GMT) we will tell them to go to bed," Vladimir Solovyov, the chief of piloted missions at the Russian segment of the ISS, told reporters after the launch.
"Their programme is quite a tense one," he said. "Space walks will start after the (New Year) holidays."
After docking with the ISS on Dec 23, the three astronauts will join American Jeff Williams and Russian Maxim Suraev who have manned the multi-billion-dollar station since October. The five men will be the station's Expedition 22.
Williams and Suraev are due to return to earth in March. Solovyov said the three astronauts launched on Monday would spend 126 days in space and return in May.
Russia's partners in exploiting the ISS are U.S. space agency NASA, the European Space Agency and the Japanese and Canadian space agencies. Moscow has said it wants to extend the life of the $100-billion ISS beyond 2015. This year Russia doubled to four the number of manned flights to the ISS aboard its single-use Soyuz spacecraft.
Solovyov said the burden on Russia to support the station was only set to grow after NASA retires its aging fleet of Space Shuttles sometime in late 2010.
"We will support the life of the station by launching our transport and cargo spacecraft," he said.
This space launch breached one of the traditions of Russia's space industry -- to abstain from launches on Mondays -- established in the time of Sergei Korolyov, the famed designer of the R-7 rocket that is a prototype of the Souyz.
"Well yes, but no worries -- the launch time was only 52 minutes into Monday," Solovyov admitted with a smile.

Genes may explain why some people are more susceptible than others to leprosy, an extensive study in China published in the New England Journal of Medicine appears to have found.The study found mutations of seven genes which appear to increase a person's susceptibility to leprosy, which is in sharp contrast to what experts have believed for a long time - that the disease is not congenital, or inherited.
"All along, people thought it was caused (only) by an infectious agent but our study found it is influenced by genetics. If a parent has the disease, it is highly likely that the child will develop the disease," one of the researchers Zhang Furen at the Shandong Provincial Institute of Dermatology and Venereology in northeast China said by telephone.
"What is interesting is that between couples, if one has the disease, the other remains uninfected for decades ... so how can this (strictly) be an infectious disease? Maybe this disease has to do with inheritability."
"What we found was that apart from the infectious agent, there is an internal reason, we found seven (susceptibility) genes ... it may have a lot to do with genetics (inherited susceptibility)," Zhang told Reuters.
The finding may have similar implications for other germs belonging to the family, like the bug that causes tuberculosis - which killed 1.8 million people last year.
The experts analyzed genes of 706 leprosy patients and 1,225 others without the disease, and mutant versions of the seven genes turned up consistently in those who had the disease. The participants were ethnic Chinese from eastern China.
Five of the genes appear to be involved in regulating the human immune system, said the researchers from China and Singapore.
"Leprosy has a long incubation period of 8 to 10 years, and once the symptoms surface, they would have caused the patient irreversible damage," Zhang said.
"But in future, if we can tell whether a person is susceptible to the disease before symptoms show, we can proceed to take preventive action."
Leprosy, or Hansen's disease, is caused by the Mycobacterium leprae. It affects the skin, mucous membranes, peripheral nerves and eyes. As nerve damage is permanent, even those who have recovered can't feel pain. Minor cuts and abrasions on fingers and toes often turn into gaping, inflamed ulcers because of unsanitary living conditions.
Although leprosy is no longer a problem in advanced countries, this discovery is important because the disease plagues many developing nations.
There were 254,525 new cases of leprosy in 2007 mostly in tropical and sub-tropical countries, according to the World Health Organization.
"In China, there are 2,000 new cases each year," Zhang said.

Technology firm Cisco Systems and the NASA space agency launched a $100 million plan on Tuesday to monitor the earth's resources, aiming to boost transparency of national commitments under a new climate treaty.World leaders and ministers from more than 190 countries are meeting this week, trying to agree the outline of a new climate pact to succeed the Kyoto Protocol.
Proof of compliance with many commitments under a new deal, for example to cut carbon emissions and preserve forests, will depend on more sophisticated data monitoring than available now.
The aim of the Planetary Skin Institute is to help existing public and private, academic and government institutions share their data and analysis, for example through new online resources.
"A lot of information is available but it's highly fractured, in a thousand different formats and a thousand different places," said Cisco's Juan Carlos Castilla-Rubio.
"Over the next three years we need at least $100 million to make it work. We have commitments of over half (and) expect to hit the target in the next month."
The non-profit joint venture would aim to boost monitoring of carbon, food systems and water scarcity.
For example it could integrate existing satellite-based and ground monitoring measurements of the carbon locked in rainforests.
That may make it simpler for tropical countries to claim rewards for storing forest carbon as proposed under a new climate deal.
A global network would be made up of seven hubs in Brazil, India, China, Africa, Japan, the European Union and the United States.
"The idea is to be open as possible," said Castilla-Rubio. "We're trying to develop an environment which allows people to get together and distribute (data and analysis)."

The United States must uphold moral standards when waging wars that are necessary and justified, President Barack Obama said on Thursday as he accepted the Nobel Prize for Peace.In a speech at the award ceremony in Oslo, Obama said violent conflict would not be eradicated "in our lifetimes," there would be times when nations would need to fight just wars and he would not stand idle in the face of threats to the American people.
"Where force is necessary, we have a moral and strategic interest in binding ourselves to certain rules of conduct. And even as we confront a vicious adversary that abides by no rules, I believe that the United States of America must remain a standard bearer in the conduct of war," he declared.
Nine days after ordering 30,000 more U.S. troops to Afghanistan to break the momentum of the Taliban, Obama acknowledged the criticism of those who have said it was wrong and premature to award the Nobel accolade to a president still in his first year in office and escalating a major war.
He said America's adherence to moral standards, even in war, was what made it different from its enemies.
"That is a source of our strength. That is why I prohibited torture. That is why I ordered the prison at Guantanamo Bay closed. And that is why I have reaffirmed America's commitment to abide by the Geneva Conventions," he said.
"We lose ourselves when we compromise the very ideals that we fight to defend. And we honor those ideals by upholding them not just when it is easy, but when it is hard," Obama said.
SANCTIONS MUST BITE
Acknowledging "a reflexive suspicion of America, the world's sole military superpower," he said his country could not act alone in confronting global challenges in Afghanistan, Somalia or other troubled regions.
In seeking alternatives to force, it was necessary to be tough.
"Those regimes that break the rules must be held accountable. Sanctions must enact a real price," Obama said in a passage that addressed North Korea's nuclear arsenal and U.S. suspicions that Iran, too, seeks to acquire the bomb.
"It is...incumbent upon all of us to insist that nations like Iran and North Korea do not game the system," Obama said. "Those who seek peace cannot stand idly by as nations arm themselves for nuclear war."
At a news conference earlier, Obama reaffirmed that U.S. troops would begin transferring responsibility for Afghan security to local forces in July 2011 but said there would be no "precipitous drawdown."
Acknowledging the controversy surrounding his prize, he said: "I have no doubt that there are others that may be more deserving. My task here is to continue on the path that I believe is not only important for America but important for lasting peace in the world."
He said that meant pursuing a world free of nuclear weapons and countering proliferation; addressing climate change; stabilizing countries like Afghanistan; "mobilizing an international effort to deal with terrorism that is consistent with our values and ideals"; and addressing development issues.
Some of these initiatives were beginning to bear fruit, Obama said.
"If I am successful in those tasks, then hopefully some of the criticism will subside, but that is not really my concern. If I am not successful, than all the praise and awards in the world will not disguise that."
Norwegian Prime Minister Jens Stoltenberg told journalists the prize was well deserved and "can contribute in itself to strengthening the efforts of the president to work for peace."
On a rainy day with temperatures just above freezing, thousands lined heavily guarded Oslo streets to greet Obama.
Only handfuls of protesters were visible, with one group holding a sign reading: "Obama you won it, now earn it."
Environmentalists in the crowd called on the U.S. leader to sign an ambitious deal to fight global warming when he visits nearby Copenhagen next week for the climax of a U.N. climate conference involving nearly 200 countries.

Virgin Atlantic on Monday unveiled the first commercial passenger spaceship, a sleek black-and-white vessel that represents an expensive gamble on creating a commercial space tourism industry.The company hopes the winged, minivan-sized SpaceShipTwo will rocket tourists into zero gravity beginning in two or three years.
"This will be the start of commercial space travel," Virgin Atlantic Airways founder and billionaire Richard Branson said at the launch in California's Mojave Desert. "You become an astronaut."
The project, with a $450 million budget, would see the construction of six commercial spaceships that would take passengers high enough to achieve weightlessness and see the curvature of Earth set against the backdrop of space.
A twin-hulled aircraft named Eve would carry SpaceShipTwo to an altitude of about 60,000 feet before releasing it. The spaceship would then fire its onboard rocket engines, climbing to about 65 miles above Earth.
The trip would take about 2-1/2 hours, with passengers experiencing about five minutes of weightlessness.
Some 300 aspiring astronauts have put down deposits for the $200,000 ride, which includes three days of training.
Eventually, Virgin Galactic, the offshoot of Virgin Atlantic, may offer suborbital travel that could dramatically cut the length of flights.
"Subject to American government permission, we may well start developing a program to try to take people from continent to continent, you know, two hours from Los Angeles to Australia," Branson said in an interview with Reuters TV.
"Can't promise that we're going to be able to do it, but if you don't try things you don't succeed, so we'll definitely give it a go," he said.
BRANSON SAYS SAFER THAN NASA
Other potential business ventures include flying scientists and experiments and launching small payloads into space.
Branson hired aircraft designer Burt Rutan and his team at Scaled Composites to build the commercial spaceship fleet after a Rutan prototype named SpaceShipOne won the $10 million Ansari X Prize in 2004 for the first private piloted spaceflight.
Commercial space flight has been a dream for decades, but the 2004 flight was the first proof that industry might be able to achieve it without the help of government, which historically has dominated space travel.
A lethal 2007 explosion during a rocket engine test by Scaled Composites, however, illustrated the danger and risk to creating a safe and profitable venture.
Branson, in the Reuters Television interview, said that the flights would be safer than NASA's Space Shuttle.
"I think because it's so much younger, it's just that much safer than what NASA has done using old technology which is 50, 60 years old," he said.
SpaceShipOne, which is on display at the National Air & Space Museum in Washington, made three suborbital flights.
A 10-month atmospheric test flight program is expected to begin on Tuesday and would be followed by extensive test flights into space before passenger travel in 2011 or 2012

An HIV genetic stowaway that may have come from a related cat virus could help the AIDS virus transmit and replicate in people, U.S. researchers reported on Sunday.Their finding, which has implications for designing new drugs or a vaccine against the fatal and incurable virus, may also shed light on how other viruses, such as swine flu, spread from animals to people, experts said.
And it also may help explain how an ancient virus came to cause the devastating 25-year-long pandemic of AIDS.
Dr. Robert Bambara of the University of Rochester Medical Center in New York and colleagues found the previously unnoticed stretch of genetic material in the RNA sequence of the virus. HIV is a so-called retrovirus -- it uses RNA, instead of DNA, to function.
This little bit of genetic material closely mimics a stretch of human RNA, they reported in the journal Nature Structural and Molecular Biology.
"We not only found the gene, but also a plausible explanation for why it is still there after millions of generations: its presence makes HIV dramatically better at reproducing inside of our cells," Bambara said in a statement.
"This suggests new ways to shut down with drugs the ability of the virus to mass produce copies of itself."
HIV is believed to have jumped to humans from a close relative called simian immunodeficiency virus or SIV, which infects chimpanzees.
"Feline immunodeficiency virus (FIV), which infects cats, is thought to be the virus from which SIV originated and therefore an ancestor of HIV," the researchers wrote.
"HIV-related viruses have been identified in sheep, goats, horse, cattle and cats, but only the cat virus FIV seems to be a close relative of HIV and SIV."
The gene Bambara's team found looks very much like human tRNALys, which HIV needs to replicate itself. Like all viruses, HIV "lives" by infecting cells, hijacking their machinery and turning them into factories that make copies of the virus.
"Determination of the origin of the tRNA-like sequence should provide valuable clues about the ancestry of HIV," the researchers wrote.
Studying this genetic sequence more may help scientists understand how viruses jump from animals to humans, added Matthew Portnoy of the National Institute of General medical Sciences, one of the National Institutes of Health.
The study "has broader implications beyond HIV research, and may impact the response to the current H1N1 flu pandemic, where that virus has jumped multiple species and picked up several parts of its genome from each of the many species it has passed through," Portnoy said in a statement.
"Understanding the mechanisms of these transfers enables researchers to better understand the evolution of viruses, and hopefully to better predict their 'next move' as they design vaccines and treatments," Portnoy said.
HIV now infects an estimated 33.4 million people, according to the United Nations, and has killed 25 million. H1N1 swine flu is still spreading globally and has infected tens of millions.

The U.S. government approved the first 13 batches of human embryonic stem cells on Wednesday, enabling researchers using them to get millions of dollars in federal funding as promised by President Barack Obama in March.The batches, known as lines, were made by two researchers at Harvard University and Rockefeller University using private funds, said Dr. Francis Collins, director of the National Institutes of Health.
"Today we are announcing the approval of the first 13 stem cell lines," Collins told reporters in a telephone briefing.
In March, Obama lifted restrictions on human embryonic stem cell research imposed by his predecessor, George W. Bush.
He could not lift a restriction set by Congress, called the Dickey-Wicker amendment, that forbids the use of federal money to make the stem cells, which require destruction of a human embryo. But the decision made it possible for researchers to use federal funds to work with cells that others have made.
The NIH set up a panel to decide which stem cell lines met strict ethical restrictions. The cells, for instance, have to have been made using an embryo donated from leftovers at fertility clinics, and parents must have signed detailed consent forms.
Stem cells are the body's ultimate master cells. They make up days-old embryos and have the power to give rise to all the cells and tissues in the body.
Scientists hope to use them to transform medicine by growing new tissue and repairing damage. Opponents say it is wrong to destroy human embryos for any reason.
ETHICALLY ACCEPTABLE
But Collins said the NIH-approved lines represent an acceptable compromise. "I think the broad consensus among most of the public ... is that stem cell research of this ethically acceptable kind should go forward," he said.
"These were derived from embryos derived under ethically sound consent processes."
The first 13 lines were "open and shut" cases, he said. Another 96 lines are under consideration and more approvals can be expected in the coming days, Collins said.
"I think people are champing at the bit," he said. "This is the first down payment in what is going to be a much longer list of such lines."
Eleven of the lines were made by Dr. George Daley of the Harvard Stem Cell Institute in Massachusetts. He said his lab started making the stem cells in 2006 using private donations and is looking forward to getting federal money.
"It is a huge boost. It is a stimulus to my research," said Daley, who said he has hired three technicians in the past two weeks.
"I can point to people and say 'Thank God for Obama -- you're here'," Daley said in a telephone interview.
"We have been very fortunate at Harvard to have been the beneficiaries of philanthropy but it has dried up in past years, in part because of the economy and in part because of the perception that the government was about to step in and clear everything up."
The NIH says it has funded 30 proposals totaling more than $20 million that would use human embryonic stem cells. Now the researchers can get the cells and get going, it said.
"This group of grants includes research using human embryonic stem cells for the therapeutic regeneration of diseased or damaged heart muscle cells, developing systems for the production of neural stem cells" among others, it said.
Collins said these cells are still needed for research even though scientists have found ways to turn ordinary cells into what resemble embryonic stem cells.
"I think one could make a very strong case that we need both," he said

The space shuttle Atlantis lands at the Kennedy

Space shuttle Atlantis touched down at its Florida home port on Friday, wrapping up an 11-day mission to deliver cargo to the International Space Station, one of NASA's final supply runs before the shuttle fleet is retired next year.Gliding through clear, blue skies, commander Charles Hobaugh circled Atlantis high over the Kennedy Space Center to burn off speed, then nosed the 100-ton space plane toward a 3-mile (4.8-km) concrete runway framed by palm trees and marshlands.
"Couldn't have picked a clearer day," Hobaugh said as he caught sight of the runway.
Atlantis touched down at 9:44 a.m. EST, capping NASA's fifth and final flight of the year and the 129th mission in shuttle program history.
"That was a picture perfect end," astronaut Chris Ferguson radioed to the crew from Mission Control in Houston. "Everybody welcome back to Earth."
Just five shuttle missions remain to complete the $100 billion orbital outpost, a project of 16 nations that has been under construction 220 miles above Earth for 11 years.
"We're entering the golden era of the International Space Station program," station crew member Bob Thirsk, with the Canadian Space Agency, said during an inflight press conference this week.
NASA is building capsule-type spaceships to replace the shuttles, which are being retired due to safety concerns and high operating costs.
NOT READY UNTIL 2015
The new ships also will enable NASA to fly astronauts to the moon and other destinations in the solar system, in addition to the station. They will not be ready until 2015 at the earliest, however.
Until then, Russian, European and Japanese cargo ships will take over the job of flying food, fuel and supplies to the outpost, though none can handle the bulky station spare parts that fit in the shuttle cargo bay.
NASA also is hoping to turn over cargo deliveries and possibly crew transport to commercial U.S. companies.
Joining the six Atlantis astronauts for the ride back to Earth was space station flight engineer Nicole Stott, who has been aboard the outpost for three months. Stott is the last station crew member scheduled to catch a ride on the shuttle.
The Russian Soyuz capsule now becomes the station's exclusive taxi, a service that costs the United States about $50 million a seat.
Three more station crew members will depart on November 30, leaving the outpost with a two-member crew for the first time since 2006. Three replacements are due to arrive on December 23. The station will remain one short of its full six-member staff until March.
During their week-long stay at the space station, the Atlantis astronauts delivered 15 tons of spare parts, supplies and science experiments, including containers of butterflies so students can monitor their development in orbit.
The astronauts also conducted three spacewalks to install communications antennas and cargo attachments, replace an airlock oxygen tank and perform some maintenance on the station's robotic crane.
Atlantis brought back the station's broken water-recycler, a system designed to purify urine and waste water into potable water. NASA hopes to figure out why the device failed in the microgravity environment of space and send up a replacement on its next shuttle mission in February.
Shuttle Endeavour and six astronauts are scheduled to blast off around February 4 with the station's final connecting hub and a six-sided, glass cupola that will give crew members a 360-degree view out the window.