Featured Research

from universities, journals, and other organizations

Breakthrough? Study Finds Dopamine Cannot Be Source Of Pleasure In Brain

Date:
March 4, 1999
Source:
University Of North Carolina At Chapel Hill
Summary:
Dopamine, a chemical messenger believed for more than two decades to be the end point of the brain's pleasure system, appears not to be that molecular reward after all, a new study shows. The University of North Carolina at Chapel Hill study suggests instead that dopamine plays an early central role in pleasure, but another chemical -- possibly serotonin -- actually rings the chimes for humans and animals alike.

CHAPEL HILL - Dopamine, a chemical messenger believed for more than two decades to be the end point of the brain's pleasure system, appears not to be that molecular reward after all, a new study shows.

The University of North Carolina at Chapel Hill study suggests instead that dopamine plays an early central role in pleasure, but another chemical -- possibly serotonin -- actually rings the chimes for humans and animals alike.

Researchers say their discovery should become important in the search for solutions to substance abuse and addiction problems, researchers say.

A report on the findings appears in the March 4 issue of the journal Nature. Authors are Drs. Paul A. Garris, a postdoctoral fellow at UNC-CH now at Illinois State University, and R. Mark Wightman, William Rand Kenan Jr. professor of chemistry at UNC-CH. Others are Michaux Kilpatrick, an M.D.-Ph.D. student in Wightman's laboratory; Dr. Melissa A. Bunin, a former graduate student doing postdoctoral work in Australia; graduate student Daren Michael, and Dr. David Walker, now a Duke University postdoctoral scientist.

In what the journal dubbed "something of a technical tour de force," the studies first involved developing a carbon fiber electrode one tenth the thickness of a human hair and coating it with glass.

"When implanted in rat brains, this micro-sensor allows us for the first time to measure very small amounts of chemical messengers, or neurotransmitters, on a split-second time scale," Wightman said. "That was not possible before."

Using their device coupled with electronic equipment, Wightman and his students can record what happens inside the brain as neurotransmitters such as dopamine interact with one another in real time. They incorporated into the work experiments pioneered by Canadian researchers in which rats quickly learn that by pressing a lever, they can receive a tiny but pleasurable shock to their brain through deep probes implanted there.

"We discovered that when we applied the electric shock to untrained rats, we clearly saw dopamine, but when the animals themselves applied the shock, little or no dopamine appeared," Wightman said. "Considering that scientists have been pretty satisfied that dopamine was the important thing, this was a big surprise."

Dopamine may be involved in learning or anticipation of reward, he said. It clearly is not responsible for continuous pleasure, however, or the chemists would have detected a lot of it when trained rats repeatedly pressed the lever, too.

The new work promises better explanations of how such abused chemicals as nicotine, alcohol, cocaine and amphetamines act in the brain, Wightman said. It also might help identify less toxic substances that could ease withdrawal and make it more successful.

"Because nobody ever had a way of making these kinds of measurements, we think this is really a big jump ahead," he said. "Often it is new technology that in fact drives new findings in science and medicine."

The National Institute of Drug Abuse and the National Institute of Neurological Disorders and Stroke supported the continuing studies. A feature on the work in Wightman's laboratory will appear in April in "Endeavors," UNC-CH's research magazine.


Story Source:

The above story is based on materials provided by University Of North Carolina At Chapel Hill. Note: Materials may be edited for content and length.


Cite This Page:

University Of North Carolina At Chapel Hill. "Breakthrough? Study Finds Dopamine Cannot Be Source Of Pleasure In Brain." ScienceDaily. ScienceDaily, 4 March 1999. <www.sciencedaily.com/releases/1999/03/990304052313.htm>.
University Of North Carolina At Chapel Hill. (1999, March 4). Breakthrough? Study Finds Dopamine Cannot Be Source Of Pleasure In Brain. ScienceDaily. Retrieved August 27, 2014 from www.sciencedaily.com/releases/1999/03/990304052313.htm
University Of North Carolina At Chapel Hill. "Breakthrough? Study Finds Dopamine Cannot Be Source Of Pleasure In Brain." ScienceDaily. www.sciencedaily.com/releases/1999/03/990304052313.htm (accessed August 27, 2014).

Share This




More Health & Medicine News

Wednesday, August 27, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

WHO Calls for Ban on E-Cigarette Sales to Minors

WHO Calls for Ban on E-Cigarette Sales to Minors

AFP (Aug. 26, 2014) The World Health Organization called Tuesday on governments should ban the sale of e-cigarettes to minors, warning that they pose a "serious threat" to foetuses and young people. Duration: 01:44 Video provided by AFP
Powered by NewsLook.com
Have You Ever Been 'Sleep Drunk?' 1 in 7 Has

Have You Ever Been 'Sleep Drunk?' 1 in 7 Has

Newsy (Aug. 26, 2014) A study published in the journal "Neurology" interviewed more than 19,000 people and found 15 percent suffer from being "sleep drunk." Video provided by Newsy
Powered by NewsLook.com
Does Medical Marijuana Reduce Painkiller Overdose Deaths?

Does Medical Marijuana Reduce Painkiller Overdose Deaths?

Newsy (Aug. 26, 2014) A new study found fewer deaths from prescription drug overdoses in states that have legalized medical marijuana. But experts disagree on the results. Video provided by Newsy
Powered by NewsLook.com
Official: British Ebola Sufferer Receiving Experimental Drug

Official: British Ebola Sufferer Receiving Experimental Drug

AFP (Aug. 26, 2014) A British nurse infected with Ebola while working in Sierra Leone is being given the same experimental drug used on two US missionaries who have recovered for the disease, doctors in London say. Duration: 00:44 Video provided by AFP
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:
from the past week

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