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:2/12/2016)... ... 12, 2016 , ... The Jones Agency, a family owned insurance company with ... a cooperative charity drive with the Tarrant Area Food Bank in the hopes of ... families in need, the Tarrant County Food Bank offers hope and security to the ...
(Date:2/12/2016)... ... 12, 2016 , ... Erlanger Agency has announced a new partnership in its ... campaign focuses on the fight against breast cancer, fundraising for a local woman named ... . , Carmen is a loving single mother of two boys who also serves ...
(Date:2/12/2016)... ... 12, 2016 , ... Donor Network West, the organ procurement organization that heals ... with San Ramon Regional Medical Center. Under the collaboration, the first of its kind, ... accommodate a more certain time frame for donor families for the recovery of organs. ...
(Date:2/12/2016)... , ... February 12, 2016 , ... For Coast Dental ... Suzan Sweeney, RDH, and dental assistant Terrell Moore shortly before 7 a.m. to volunteer ... of dental professionals, donating their time and skills to help hundreds of uninsured and ...
(Date:2/12/2016)... York, NY (PRWEB) , ... February 12, 2016 ... ... edition of “Revolutionizing Cancer Care.” , The print component of “Revolutionizing ... Chicago, Dallas, Pittsburgh/Cleveland, New York, Washington DC/Baltimore, and Seattle, with a circulation of ...
Breaking Medicine News(10 mins):
(Date:2/12/2016)... , Maharashtra, February 12, 2016 ... Market research report titled Chronic Inflammation Global Clinical ... a snapshot of the global clinical trials landscape ... clinical trials by Region, Country (G7 & E7), ... point status and reviews top companies involved and ...
(Date:2/11/2016)... 2016 Laboratory glassware and plasticware ... These may range from microscope slides to large storage ... from borosilicate glass because of its low weight and ... hand, started gaining popularity over the past decade when ... glass with plastic in several applications due to its ...
(Date:2/11/2016)... 11, 2016 Potrero Medical, Inc., the developer of ... the appointment of George M. Rapier, III , MD, ... TX , WellMed is one of the nation,s largest ... HMO members in Texas and ... of his own internal medicine practice, he has been instrumental ...
Breaking Medicine Technology: