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 October 22, 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 October 22, 2014).

Share This



More Health & Medicine News

Wednesday, October 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Orthodontist Mom Jennifer Salzer on the Best Time for Braces

Orthodontist Mom Jennifer Salzer on the Best Time for Braces

Working Mother (Oct. 22, 2014) Is your child ready? Video provided by Working Mother
Powered by NewsLook.com
U.S. Issues Ebola Travel Restrictions, Are Visa Bans Next?

U.S. Issues Ebola Travel Restrictions, Are Visa Bans Next?

Newsy (Oct. 22, 2014) Now that the U.S. is restricting travel from West Africa, some are dropping questions about a travel ban and instead asking about visa bans. Video provided by Newsy
Powered by NewsLook.com
US to Track Everyone Coming from Ebola Nations

US to Track Everyone Coming from Ebola Nations

AP (Oct. 22, 2014) Stepping up their vigilance against Ebola, federal authorities said Wednesday that everyone traveling into the US from Ebola-stricken nations will be monitored for symptoms for 21 days. (Oct. 22) Video provided by AP
Powered by NewsLook.com
Doctors Help Paralysed Man Walk Again, Patient in Disbelief

Doctors Help Paralysed Man Walk Again, Patient in Disbelief

AFP (Oct. 22, 2014) Polish doctors describe how they helped a paralysed man walk again, with the patient in disbelief at the return of sensation to his legs. Duration: 1:04 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:

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