Featured Research

from universities, journals, and other organizations

Morphine Makes Lasting -- And Surprising -- Change In The Brain

Date:
April 26, 2007
Source:
Brown University
Summary:
New findings may help explain the origins of addiction in the brain. The research also supports a provocative new theory of addiction as a disease of learning and memory.

Morphine stops the synapse-strengthening process in the brain known as long-term potentiation at inhibitory synapses, according to new research conducted by Brown University brain scientist Julie Kauer. In Nature, Kauer explains this startlingly persistent effect, which could contribute to addiction and may provide a target for treatments of opioid addiction. The research also supports a provocative theory of addiction as a disease of learning and memory.

Related Articles


Morphine, as little as a single dose, blocks the brain’s ability to strengthen connections at inhibitory synapses, according to new Brown University research published in Nature.

The findings, uncovered in the laboratory of Brown scientist Julie Kauer, may help explain the origins of addiction in the brain. The research also supports a provocative new theory of addiction as a disease of learning and memory.

“We’ve added a new piece to the puzzle of how addictive drugs affect the brain,” Kauer said. “We’ve shown here that morphine makes lasting changes in the brain by blocking a mechanism that’s believed to be the key to memory making. So these findings reinforce the notion that addiction is a form of pathological learning.”

Kauer, a professor in the Department of Molecular Pharmacology, Physiology and Biotechnology at Brown, is interested in how the brain stores information. Long-term potentiation, or LTP, is critical to this process.

In LTP, connections between neurons – called synapses, the major site of information exchange in the brain – become stronger after repeated stimulation. This increased synaptic strength is believed to be the cellular basis for memory.

In her experiments, Kauer found that LTP is blocked in the brains of rats given as little as a single dose of morphine. The drug’s impact was powerful: LTP continued to be blocked 24 hours later – long after the drug was out of the animal’s system. “The persistence of the effect was stunning,” Kauer said. “This is your brain on drugs.”

Kauer recorded the phenomenon in the ventral tegmental area, or VTA, a small section of the midbrain that is involved in the reward system that reinforces survival-boosting behaviors such as eating and sex – a reward system linked to addiction. The affected synapses, Kauer found, were those between inhibitory neurons and dopamine neurons. In a healthy brain, inhibitory cells would limit the release of dopamine, the “pleasure chemical” that gets released by naturally rewarding experiences. Drugs of abuse, from alcohol to cocaine, also increase dopamine release.

So the net effect of morphine and other opioids, Kauer found, is that they boost the brain’s reward response. “It’s as if a brake were removed and dopamine cells start firing,” she explained. “That activity, combined with other brain changes caused by the drugs, could increase vulnerability to addiction. The brain may, in fact, be learning to crave drugs.”

Kauer and her team not only recorded cellular changes caused by morphine but also molecular ones. In fact, the researchers pinpointed the very molecule that morphine disables – guanylate cyclase. This enzyme, or inhibitory neurons themselves, would be effective targets for drugs that prevent or treat addiction.

Fereshteh Nugent, a Brown postdoctoral research associate, and Esther Penick, a former Brown postdoctoral research associate who now serves as assistant professor of biology at Knox College, rounded out the research team.

The National Institute of Drug Abuse funded the work.


Story Source:

The above story is based on materials provided by Brown University. Note: Materials may be edited for content and length.


Cite This Page:

Brown University. "Morphine Makes Lasting -- And Surprising -- Change In The Brain." ScienceDaily. ScienceDaily, 26 April 2007. <www.sciencedaily.com/releases/2007/04/070425142116.htm>.
Brown University. (2007, April 26). Morphine Makes Lasting -- And Surprising -- Change In The Brain. ScienceDaily. Retrieved December 19, 2014 from www.sciencedaily.com/releases/2007/04/070425142116.htm
Brown University. "Morphine Makes Lasting -- And Surprising -- Change In The Brain." ScienceDaily. www.sciencedaily.com/releases/2007/04/070425142116.htm (accessed December 19, 2014).

Share This


More From ScienceDaily



More Mind & Brain News

Friday, December 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Researchers Test Colombian Village With High Alzheimer's Rates

Researchers Test Colombian Village With High Alzheimer's Rates

AFP (Dec. 19, 2014) In Yarumal, a village in N. Colombia, Alzheimer's has ravaged a disproportionately large number of families. A genetic "curse" that may pave the way for research on how to treat the disease that claims a new victim every four seconds. Duration: 02:42 Video provided by AFP
Powered by NewsLook.com
Prenatal Exposure To Pollution Might Increase Autism Risk

Prenatal Exposure To Pollution Might Increase Autism Risk

Newsy (Dec. 18, 2014) Harvard researchers found children whose mothers were exposed to high pollution levels in the third trimester were twice as likely to develop autism. Video provided by Newsy
Powered by NewsLook.com
Yoga Could Be As Beneficial For The Heart As Walking, Biking

Yoga Could Be As Beneficial For The Heart As Walking, Biking

Newsy (Dec. 17, 2014) Yoga can help your weight, blood pressure, cholesterol and heart just as much as biking and walking does, a new study suggests. Video provided by Newsy
Powered by NewsLook.com
1st Responders Trained for Autism Sensitivity

1st Responders Trained for Autism Sensitivity

AP (Dec. 16, 2014) More departments are ordering their first responders to sit in on training sessions that focus on how to more effectively interact with those with autism spectrum disorder (Dec. 16) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins