Navigation Links
Cocaine's effects on brain metabolism may contribute to abuse
Date:2/18/2008

UPTON, NY - Many studies on cocaine addiction - and attempts to block its addictiveness - have focused on dopamine transporters, proteins that reabsorb the brain's "reward" chemical once its signal is sent. Since cocaine blocks dopamine transporters from doing their recycling job, it leaves the feel-good chemical around to keep sending the pleasure signal. Now a new study conducted at the U.S. Department of Energy's Brookhaven National Laboratory suggests that cocaine's effects go beyond the dopamine system. In the study, cocaine had significant effects on brain metabolism, even in mice that lack the gene for dopamine transporters.

"In dopamine-transporter-deficient mice, these effects on metabolism are clearly independent of cocaine's effects on dopamine," said Brookhaven neuroscientist Panayotis (Peter) Thanos, who led the research. "These metabolic factors may be a strong regulator of cocaine use and abuse, and may also suggest new avenues for addiction treatments." The study will appear in the May 2008 issue of the journal Synapse, and will be available online on Monday, February 18, 2008.

The scientists used positron emission tomography, or PET scanning, to measure brain metabolism in dopamine-transporter deficient mice (known as DAT knockouts) and in littermates that had normal dopamine transporter levels. In this technique, the scientists administer a radioactively labeled form of sugar (glucose) - the brain's main "fuel" - and use the PET scanner to track its site-specific concentrations in various brain regions. They tested the mice before and after cocaine administration, and compared the results to mice treated with saline instead of the drug.

Before any treatment, mice lacking dopamine transporters had significantly higher metabolism in the thalamus and cerebellum compared with normal mice. This elevated metabolism may be linked to chronically high levels of dopamine in the DAT knockout mice. It also suggests that dopamine levels may play an important role in modulating glucose levels in these brain areas, which play important roles integrating sensory information, learning, and motor function.

Interestingly, DAT knockout mice have been suggested as an animal model for attention-deficit hyperactivity disorder (ADHD). Elevated metabolism due to persistent elevated dopamine levels may be a factor contributing to the symptoms of ADHD, Thanos said.

After the scientists administered cocaine, whole brain metabolism decreased in both groups of mice, but more significantly in normal mice than in DAT knockouts. The scientists were able to detect this reduction in metabolism in a wide range of brain regions in the normal mice, suggesting that these decreases in metabolism are somehow associated with the blockade of dopamine transporters by cocaine.

The scientists also observed a reduction in metabolism in the thalamus region in the DAT knockout mice. This effect may likely be due to the effect of cocaine on other neurotransmitter systems, for example, norepinepherine or serotonin.

In summary, cocaine exposure has an effect on regional brain activity, which is mostly driven by dopamine action and to a secondary degree norepinephrine or serotonin. These results also support the idea that the thalamus and the cerebellum play key roles in cocaine's mechanism of effect on sensory input, learning, and motor function. This is particularly of interest in better understanding the mechanism of cocaine addiction as well as the neurobiology of ADHD.


'/>"/>

Contact: Karen McNulty Walsh
kmcnulty@bnl.gov
631-344-8350
DOE/Brookhaven National Laboratory
Source:Eurekalert

Related medicine news :

1. New study may explain Vioxx side-effects
2. 13 percent of women stop taking breast cancer drug because of side effects, U-M study finds
3. Natural aorta grafts have few side effects for infection-prone patients
4. New Report: Dangerous Drug Side Effects and Deaths Doubled Since 1998... Seniors Hit Hardest
5. Detroit Metro Tower Air Traffic Controllers File Lawsuit Alleging Improper Mold Removal and Health Effects
6. Empowerment Program Gets Patients on the PATH to Managing the Physical and Emotional Effects of Psoriatic Arthritis
7. Shaking may cause brain damage and serious long-term effects to infants
8. Smoking can harm the long-term effects of some oral surgery procedures
9. ECLIPSE data on effects of Otsukas investigational novel treatment, Tolvaptan
10. Combination therapy reverses effects of portal hypertension in rats
11. Fighting the Gassy Effects of Good Eating, From the Harvard Health Letter
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:5/22/2017)... San Antonio, TX (PRWEB) , ... May 22, 2017 , ... ... It starts with a body squatted, stretched, jumped, toned and shaped through fitness programs. ... And it is, of course, finished off with an irresistible, radiant smile. CDA ...
(Date:5/21/2017)... ID (PRWEB) , ... May 20, 2017 , ... ... financial integration systems between ABC Financial Services and financial systems. , ... link or exported files that are electronically processed through GetLinked into their club’s ...
(Date:5/21/2017)... ... ... For more than 20 years United Cutlery has been distinguished by unique and ... to fantasy. United Cutlery has always been “Stronger. Sharper” than the competition and it ... a range of weapons and tools built for battle, the M48 line by United ...
(Date:5/19/2017)... ... May 19, 2017 , ... ... an upcoming episode of Innovations with Ed Begley, Jr., airing fourth quarter 2017 ... distributor of a clean, organic dietary supplement made from naturally occurring ingredients. Innovations ...
(Date:5/19/2017)... , ... May 19, 2017 , ... ... 2017 class of Beckman Young Investigators: , Victor Acosta, Ph.D. - University of ... University, Dan Fu, Ph.D. - University of Washington, Erik Grumstrup, Ph.D. - Montana ...
Breaking Medicine News(10 mins):
(Date:5/4/2017)... May 4, 2017  A new tight-tolerance microextrusion ... other highly-engineered materials, is being launched by Natvar, ... been developed in recent years to service a ... surgical applications. More expensive materials such as glass ... tubing due to their ability to consistently hold ...
(Date:5/3/2017)... , May 3, 2017  Kalorama Information notes ... nine percent next year and this is projected ... hematopoietic stem cell (HSCT) or bone marrow transplants ... technologies are well-suited for this task. This according ... publisher Kalorama Information. The various PCR-based methodologies, Sanger ...
(Date:5/2/2017)... and LONDON , May ... market intelligence, MarketResearch.com is pleased to announce a business ... that allows for the marketing and distribution of ... through the MarketResearch.com website. The new relationship ... complete product descriptions and tables of contents from research ...
Breaking Medicine Technology: