Featured Research

from universities, journals, and other organizations

Chemical system in brain behaves differently in cocaine addicts, scientists find

Date:
August 11, 2010
Source:
UT Southwestern Medical Center
Summary:
Researchers have identified a chemical system in the brain that reacts differently in cocaine addicts, findings that could result in new treatment options for individuals addicted to the drug.

UT Southwestern Medical Center researchers have identified a chemical system in the brain that reacts differently in cocaine addicts, findings that could result in new treatment options for individuals addicted to the drug.

Related Articles


"We found that the amount of blood flow in areas of the brain known to be involved in the rewarding effects of cocaine and craving was different in cocaine addicts, compared with healthy subjects," said Dr. Bryon Adinoff, professor of psychiatry at UT Southwestern and lead author of a study that appeared in Neuropsychopharmacology. "Now we have a new target for pharmacologic intervention."

The researchers studied changes in the brain's cholinergic system, which involves the neurotransmitter acetylcholine and its receptors, or docking points, on brain cells to which the chemical attaches. Disruption of this system has been implicated in Alzheimer's disease. In animal models of addiction, the neurotransmitter has been shown to affect how hard an animal will work to get a drug, but until now, the cholinergic system's relation to addiction in humans hadn't been explored.

For this study, researchers looked at how alterations in the cholinergic system affected the limbic region in the brain of cocaine-addicted subjects. The limbic region of the brain supports functions such as emotions, behavior, learning and long-term memory. It includes brain structures such as the hippocampus and amygdala.

Much addiction-related work has focused on other chemicals in the brain, particularly dopamine. Dopamine is associated with the "pleasure system" of the brain and is released by naturally rewarding experiences such as food, sex and the use of drugs like cocaine.

"Very few treatments affecting these other chemical systems have been effective at helping cure addiction," said Dr. Michael Devous, professor of radiology at UT Southwestern and an author of the paper. "We have discovered abnormalities in the cholinergic system of cocaine addiction that may relate more to the addictive process than the reward process."

On two different days, researchers injected two substances known to be safe in humans into 22 healthy subjects and 23 cocaine addicts who had abstained from the drug for one to six weeks. The substances -- scopolamine and physostigmine -- act on acetylcholine receptors. On the third day, subjects were given saline. After each injection, subjects underwent brain scans using single photon emission computed tomography (SPECT) to look at blood flow in the limbic region.

"It's a complicated system," said Dr. Adinoff, holder of the Distinguished Professorship in Drug and Alcohol Abuse Research. "The idea was to push it; it didn't matter whether the system was more active or less active, we just wanted to see if it changed."

Both scopolamine and physostigmine induced blood flow changes in limbic brain regions, but the flow patterns were different in cocaine addicts and healthy subjects.

One of the most intriguing areas affected by both substances was the tail of the hippocampus, Dr. Adinoff said. Other research has shown that this section controls environmental cues that may make someone more likely to continue to use cocaine.

"That makes sense," Dr. Adinoff said. "It's a very specific and isolated region with lots of cholinergic receptors."

The amygdala, which is involved with cue-induced cravings, also was affected by pushing the cholinergic system.

"Both of these areas of the brain are relevant to drug cravings and reward, so perhaps we could inhibit desire for a drug by giving medication that would affect these systems," Dr. Adinoff said.

Dr. Adinoff said the next step would be to use functional magnetic resonance imaging (fMRI) to assess how the cholinergic system affects decision-making processes in addicts that heighten the risk of relapse.

Other UT Southwestern researchers participating in this study were Dr. Mark Williams, adjunct assistant professor of psychiatry; Dr. Susan Best, clinical associate professor of psychiatry; Thomas Harris, senior research scientist in radiology; Dr. Abu Minhajuddin, assistant professor of clinical sciences; and Dr. Munro Cullum, chief of psychology. Dr. Tanya Zielinski, formerly of UT Southwestern also participated in the study.

The research was funded by the National Institutes of Health and the Veterans Affairs North Texas Health Care System. Ceretec, an imaging agent, was provided by GE Healthcare.


Story Source:

The above story is based on materials provided by UT Southwestern Medical Center. Note: Materials may be edited for content and length.


Cite This Page:

UT Southwestern Medical Center. "Chemical system in brain behaves differently in cocaine addicts, scientists find." ScienceDaily. ScienceDaily, 11 August 2010. <www.sciencedaily.com/releases/2010/08/100810122202.htm>.
UT Southwestern Medical Center. (2010, August 11). Chemical system in brain behaves differently in cocaine addicts, scientists find. ScienceDaily. Retrieved October 25, 2014 from www.sciencedaily.com/releases/2010/08/100810122202.htm
UT Southwestern Medical Center. "Chemical system in brain behaves differently in cocaine addicts, scientists find." ScienceDaily. www.sciencedaily.com/releases/2010/08/100810122202.htm (accessed October 25, 2014).

Share This



More Mind & Brain News

Saturday, October 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Academic Scandal Shocks UNC

Academic Scandal Shocks UNC

AP (Oct. 23, 2014) A scandal involving bogus classes and inflated grades at the University of North Carolina was bigger than previously reported, a new investigation found. (Oct. 23) Video provided by AP
Powered by NewsLook.com
Working Mother Getaway: Beaches Turks & Caicos

Working Mother Getaway: Beaches Turks & Caicos

Working Mother (Oct. 22, 2014) Feast your eyes on this gorgeous family-friendly resort. Video provided by Working Mother
Powered by NewsLook.com
What Your Favorite Color Says About You

What Your Favorite Color Says About You

Buzz60 (Oct. 22, 2014) We all have one color we love to wear, and believe it or not, your color preference may reveal some of your character traits. In celebration of National Color Day, Krystin Goodwin (@kyrstingoodwin) highlights what your favorite colors may say about you. Video provided by Buzz60
Powered by NewsLook.com
First-Of-Its-Kind Treatment Gives Man Ability To Walk Again

First-Of-Its-Kind Treatment Gives Man Ability To Walk Again

Newsy (Oct. 21, 2014) A medical team has for the first time given a man the ability to walk again after transplanting cells from his brain onto his severed spinal cord. Video provided by Newsy
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