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:6/27/2016)... Lafayette, California (PRWEB) , ... ... ... a pioneer in the patient payment industry today announced its strategic partnership ... and health system workflows. , The two companies’ proven, proprietary technology combine ...
(Date:6/27/2016)... ... 27, 2016 , ... TopConsumerReviews.com recently awarded their highest five-star rating to Best ... individuals in the United States and Canada wear eyeglasses. Once considered to be a ... and make a fashion statement. Even celebrities use glasses as a way of creating ...
(Date:6/26/2016)... ... June 26, 2016 , ... On June 10-11, 2016, A Forever Recovery, ... Festival and World’s Longest Breakfast Table in Battle Creek, MI, where the rehabilitation facility ... home to some of the world’s leading providers of cereal and other breakfast foods. ...
(Date:6/26/2016)... Carolina (PRWEB) , ... June 26, 2016 , ... ... of a new product that was developed to enhance the health of felines. The ... centuries. , The two main herbs in the PawPaws Cat Kidney Support ...
(Date:6/26/2016)... Lake Orion, Clarkston, Michigan (PRWEB) , ... June ... ... direction with respect to fertility once they have been diagnosed with endometriosis. These ... tolerable intercourse but they also require a comprehensive approach that can help for ...
Breaking Medicine News(10 mins):
(Date:6/24/2016)... 24, 2016 Research and ... "Structural Electronics 2015-2025: Applications, Technologies, Forecasts" report ... In-Mold Electronics, Smart Skin, Structural Health Monitoring, ... Structural electronics involves electronic and/or electrical components ... replacing dumb structures such as vehicle bodies or ...
(Date:6/24/2016)... According to a new market ... Needles, Safety Pen Needles), Needle Length (4mm, 5mm, 6mm, ... of Purchase (Retail, Non-Retail) - Trends & Global Forecasts ... market for the forecast period of 2016 to 2021. ... by 2021 from USD 1.65 Billion in 2016, growing ...
(Date:6/23/2016)... 2016 Research and Markets has announced ... Forecast to 2022" report to their offering. ... the patients with kidney failure, it replaces the function of ... patient,s blood and thus the treatment helps to keep the ... balance. Increasing number of ESRD patients & ...
Breaking Medicine Technology: