November 28, 2014 01:22 UTC

Science & Technology

American Researchers End Drug-Seeking Behavior in Rats

In this story we tell about an experimental way to cure drug dependency in rats.

A Colombian police officer walks near packs of confiscated marijuana and cocaine.
A Colombian police officer walks near packs of confiscated marijuana and cocaine.

Multimedia

Play or download an MP3 of this story
  • American Researchers Able to End Drug-Seeking Behavior in Rats

From VOA Learning English, this is Science In The News. I’m Mario Ritter.

And I’m Jeri Watson. Today we tell about an experimental way to cure drug dependency in rats. We also tell about a health threat to one third of all adults. We have a report on a gene that controls the ability of the heart to repair itself. And we report on a competition for researchers with expertise in neurobiology.

Drug addiction might be cured with a simple treatment to awaken a part of the brain of the addict – the person who has grown dependent on the drug. Recently, researchers reported they were able to end drug-seeking behavior in rats addicted to cocaine. They said they did this with laser light by activating a part of the animals’ brains known as the prefrontal cortex.

Cocaine is used widely as a drug. It comes from a substance, an alkaloid, in the coca plant. For several weeks, the researchers gave the drug to a group of rats. The animals quickly became dependent on cocaine.

For four days, the rats received a mild but unpleasant electric shock to a foot when they attempted to get more cocaine.

Antonello Bonci is scientific director at the United States National Institute on Drug Abuse. He was involved in the study. He says that after the shocks, 70 percent of the rats stopped looking for more cocaine. But the remaining 30 percent continued to show an addictive hunger for the drug.

The researchers compared nerve-cell firing action in both groups of rats by examining cells from a brain area known as the prefrontal cortex. This area is involved in higher brain activity. This includes the making of decisions, controlling unplanned behavior and unwillingness to change one’s mind.

Scientists discovered that the addicted rats had reduced activity in a part of the brain cortex called the prelimbic region. The area showed weakness in the self-control processes needed to resist the drug. So, the scientists developed a plan to increase the animal’s ability to control itself.

The first step was to inject the brain area with a harmless virus carrying a protein that responds to light. After several weeks, the scientists placed a very small fiber optic device into the prefrontal cortex, and sent light to wake up the sleepy area.

Antonello Bonci praised the results.

“When we turned on some activity in this prefrontal cortex, we could see that the compulsive cocaine seeking was gone.”

He says researchers then turned the process around. The rats that had changed their behavior because of the shocks again became cocaine seekers. This happened because the researchers used the fiberoptic method to reduce neuronal firing in the prefrontal cortex.

Dr. Bonci says investigators are now designing human clinical tests for electromagnetic brain stimulation that is non-invasive. He says they are doing this to increase the hypoactive, or inactive, prefrontal cortex of volunteer drug users.

He says the plan is to set up testing in the near future. In those trials, he says, cocaine addicts ideally should lose their interest and need for the drug.

The heart is our life force. It pumps blood, carrying oxygen to every organ in the body. As the blood flows through the blood vessels, it puts pressure on the vessel walls.

That pressure is often measured when you go to see a doctor or a health care worker. Blood pressure readings are often taken with a cuff, or restraint, tightened around the upper arm.

George Thomas is with the Cleveland Clinic in Ohio.

“When you go to the doctor, you may see that the blood pressure is reported as two numbers. So there’s an upper number, which is called a systolic blood pressure, and there’s a lower number that is called a diastolic pressure.”

The upper number shows the pressure inside the blood vessels when the heart is pumping. The lower number shows the pressure when the heart rests between beats.

Stephen Havas is with the University of Maryland School of Medicine. He says both numbers are important.

“Any level above 115 systolic or 75 diastolic increases risk. Each 20 millimeters systolic that you go above that 115, your risk doubles.”

Higher numbers are evidence of hypertension, the word that doctors use for high blood pressure. Hypertension is a major cause of heart disease, stroke and death.

The World Health Organization recently urged the medical community to strengthen efforts to prevent and control high blood pressure. World Health Organization officials say one-third of people over the age of 25 have the condition. Yet many of them do not know they have it.

With high blood pressure, the heart must pump harder. That weakens the heart muscle and can lead to heart attack or heart failure. There is no identifiable cause for 95 percent of those with high blood pressure, but there are clues. With age, blood vessels can become harder. Genetics also has an influence, as does family history.

Being overweight can also cause blood pressure to rise. Stephen Havas says so can smoking and eating food that contains a lot of salt.

“When I ask people about salt in their diet, they usually say they don’t add salt. That’s a good thing. But, you should also remember that most salt or sodium comes from processed foods.”

The human body needs only 150 milligrams of salt a day. But most Americans take in between three thousand and four thousand milligrams a day!

“The deaths attributed to excess salt consumption represent a huge toll – the equivalent of a jumbo jet with more than 400 adults crashing every day of the year, year after year.”

Doctors say a good diet can help control high blood pressure. Losing weight and not smoking also can help to control hypertension. Finally, experts say regular medical visits are the best protection against this silent killer.

Researchers say they have identified a gene that controls the ability of the heart to repair itself after a heart attack or other injury. The announcement came from scientists at the University of Texas. They had shown earlier that a newborn mammal could regenerate heart cells and repair injuries through cell division. But they found the heart lost that ability as the animal developed.

The scientists found that a gene called Meis1 became very active in heart cells soon after birth, when the heart muscles stop dividing. They soon began wondering about Meis1 and its importance.

The research team removed Meis1 from the heart of newborn mice. They then showed that the period for regenerating cells was lengthened. The researchers were also able to re-activate this regenerative process in adult mouse hearts by removing the gene.

Hesham Sadek led the University of Texas team. He says Meis1 controls several genes that normally stop cell division. He compared this to an on-off switch for making adult heart cells divide.

The researchers say the finding could provide a new way to study heart regeneration. In Dr. Sadek’s words, “it could introduce a new era in treatment for heart failure.” Many researchers currently are studying the possible use of stem cells to replace damaged heart cells.

A report on the University of Texas study was published in the journal Nature.

Eppendorf and the journal Science have begun accepting nominations for the 2013 Eppendorf & Science Prize for Neurobiology. The prize is presented each year for research in neurobiology.

The competition is open to scientists who are 35 years old or younger. A committee of experts will choose the grand prize winner. All nominations must be received by June 15. The winner will receive 25 thousand dollars.

An American scientist won the Eppendorf & Science Prize for Neurobiology last year. Marlene Cohen is an assistant professor in the Department of Neuroscience and the Center for the Neural Basis of Cognition at the University of Pittsburgh. She studies how we use visual images to gather information about the world.

The Eppendorf award committee praised her work. The committee said it provided a new way to study how our mental activity affects what we observe and how mental processes such as attention are controlled.

Marlene Cohen and other researchers trained animals to take a test. The test measured their ability to recognize small changes taking place around them. The animals could see these changes if they examined nearby objects carefully.

The researchers studied nerve cells called neurons in the animals. Neurons process and send information through electrical and chemical signals. The researchers noted changes in the cells when the animals lost interest in an object. They said that when these changes took place, the animals did not perform well and the effect was huge.

As Marlene Cohen noted, “when the animals paid attention to the correct location, they could recognize a change about 75 percent of the time. When their attention wandered, they detected the change less than 10 percent of the time.”

Her report was published last year in the journal Science. The magazine’s senior editor, Peter Stern, is leading the committee that will choose the 2013 Eppendorf & Science Prize for Neurobiology. Eppendorf is based in Germany. The company develops and manufactures laboratory equipment.

This Science In The News was written by Jerilyn Watson and George Grow and. Our producer was June Simms. I’m Mario Ritter.

And I’m Jerilyn Watson. Join us again next week for more news about science in Special English on the Voice of America.



This forum has been closed.
Comment Sorting
Comments
     
by: Jose from: Madrid
05/02/2013 9:38 AM
Thank you for the article.You can learn American English and you update in different issues .


by: Rafael
05/01/2013 8:53 PM
I didn't understand this question.
A Whale, a sealion are mammals and they are able to swim. Aren't they?


by: Anonymous
05/01/2013 3:27 PM
many texts can't be heared.


by: pablo from: ecuador
05/01/2013 4:07 AM
it is very useful to enhance my awareness in english.

Learn with The News

  • Audio North Korea Warns of Punishment for US, Allies

    North Korea said it would punish countries that supported a UN resolution condemning North Korea's human rights record. The recent U.N. committee vote called on the Security Council to send North Korea to the International Criminal Court for suspected violations, including torture and murder. More

  • A Libyan military soldier fires his weapon during clashes with Islamic extremist militias in Benghazi, Libya, Thursday, Oct. 30, 2014. Government troops entered central Benghazi Wednesday after nearly 10 days of fighting Islamic extremist militias, a mili

    Audio Unrest, Abuse Prevent Solution in Libya

    Amnesty International is condemning all sides in Libya for human rights abuses and violations of international law. The rights group is calling on militia commanders to end the abuses. But that call is unlikely to have much of an effect on the commanders, who have never been punished. More

  • New members of the Afghan National Army attend their graduation ceremony at the Afghan Military Academy in Kabul, Afghanistan, Nov. 23, 2014.

    Audio US Says Military Operations in Afghanistan Remain the Same

    Also in the news, India-Pakistan tensions remain at a major South Asia conference in Kathmandu, Nepal; Hong Kong police arrest student leaders and clear streets around Mong Kok; The Revolutionary Armed Forces (FARC) of Colombia frees two soldiers to restart peace talks with the government. More

  • Video Thanksgiving, a Traditional American Holiday

    Thanksgiving is celebrated every year on the fourth Thursday of November. The month of November comes in autumn, the main season for harvesting crops. Thanksgiving is an autumn harvest festival like those found in many cultures. It is viewed as the most traditional of all American holidays. More

  • A flock of 30-pound tom turkeys mill around in the barn at  Raymond's Turkey Farm in Methuen, Mass.,Tuesday, Nov. 21, 2006. The 60-acre farm expects to sell about 9,000 turkeys this holiday season.(AP Photo/Elise Amendola)

    Audio Turkey: A Case of Mistaken Identity

    Many think the bird comes from the nation of Turkey. But turkey is not from Turkey. In fact, the fact that the turkey bird is called by that name is one big mistake. Find out in today's Words and Their Stories. More

Featured Stories

  • Battle of Cold Harbor

    Audio Strong Defense at Cold Harbor Gives Lee His Last Major Victory

    After Northern forces defeated Southern troops at Gettysburg, Pennsylvania and Vicksburg, Mississippi, General Ulysses Grant decided to hit the Confederates with the full force of the Union armies. The fight did not go as he expected. But General Grant was resolved to defeat the Confederates. More

  • Alzheimer brain

    Audio East Meets West to Treat Alzheimer's Patients

    But researchers in California say a new way of treating Alzheimer’s disease is showing promise for reversing some of that memory loss. The new treatment combines western medicine with eastern philosophy – ideas rooted in Asian religions. More

  • Mr. Van Rijsselberghe worked on the project with scientists from the Free University of Amsterdam.

    Video Dutch Experiment Grows Vegetables in Sea Water

    Due to rising sea level, farmers are increasingly unable to use fields close to the sea. A farmer in the Netherlands is growing small, but healthy and tasty crops in a mixture of fresh and salt water. Farmers in Pakistan may soon be growing Dutch potatoes in areas affected by rising sea waters. More

  • Jonathan Evans Performs with Bonerama

    Video With Bonerama, Three Trombones Lead the Big Parade

    The New Orleans-based group brings together funk, rock, blues and jazz, creating a gumbo for the ears. Bonerama has horns like many bands. But, unlike most groups, the trombone players lead this band. Reporter Jonathan Evans performed with the band and wrote about it for American Mosaic. More

  • A line from Abraham Lincoln's Gettysburg Address is displayed at the Lincoln Memorial in Washington, DC.

    Audio Lincoln's Words at Gettysburg Still Have Meaning

    On November 19, 1863, President Abraham Lincoln said no one would remember his speech at a battlefield cemetery in Gettysburg, Pennsylvania. But Lincoln’s Gettysburg Address remains one of the most important speeches in U.S. history. | The Making of a Nation More

Practice Your Writing

Confessions of an English Learner BlogConfessions of an English Learner Blog

Tell us About Our Programs