Navigation Links
Definite Connection Between Receptor Levels and Cocaine Abuse Reveals PET Imaging

Now, researchers adopting the technique of positron emission tomography (PET) have been able to confirm a link between a distinct character in the brain chemistry// and the susceptibility of an individual to resort to cocaine , to the extent of even becoming an addict.

The research, in animals, shows a significant correlation between the number of receptors in part of the brain for the neurotransmitter dopamine – measured before cocaine use begins – and the rate at which the animal will later self-administer the drug. The research was conducted in rhesus monkeys, which are considered an excellent model of human drug users.

Generally the lower the initial number of dopamine receptors, the higher the rate of cocaine use, the researchers found. The research was led by Michael A. Nader, Ph.D., professor of physiology and pharmacology at Wake Forest University School of Medicine.

It was already known that cocaine abusers had lower levels of a particular dopamine receptor known as D2, in both human and animal subjects, compared to non-users. But it was not known whether that was a pre-existing trait that predisposed individuals to cocaine abuse or was a result of cocaine use.

"The present findings in monkeys suggest that both factors are likely to be true," Nader and colleagues write in a study published online this week in the journal Nature Neuroscience. "The present findings also suggest that more vulnerable individuals are even more likely to continue using cocaine because of the cocaine-induced reductions in D2 receptor levels."

This was the first study ever to measure the baseline D2 levels of animals that had never used cocaine and compare those levels to changes in D2 receptors after the animals had started using. This kind of comparison is not possible with human subjects, and in previous monkey research, the brain chemistry of animals exposed to cocaine was compared only with non-using "controls."
< br> The research also showed that starting to use cocaine caused the D2 levels to drop significantly and that continuing to use the drug kept the D2 levels well below the baseline.

"Overall, these findings provide unequivocal evidence for a role of [dopamine] D2 receptors in cocaine abuse and suggest that treatments aimed at increasing levels of D2 receptors may have promise for alleviating drug addition," the researchers write.

The study suggested that increasing D2 receptors might be done "pharmacologically" or by improving environmental factors, such as reducing stress. But, the study notes, "at present there are no clinically effective therapies for cocaine addiction, and an understanding of the biological and environmental mediators of vulnerability to cocaine abuse remains elusive."

Dopamine, like other neurotransmitters, moves between nerve cells in the brain to convey certain "messages." It is released by one nerve cell and taken in by the receptors on the next nerve cell, some of which are D2. Unused dopamine is collected in "transporters" that return it to the sending cell.

Cocaine operates by entering the transporter, blocking the "reuptake" of dopamine and leaving more of it in the space between the cells. It is thought that this overload of dopamine gives the user the cocaine "high."

But this dopamine overload also overwhelms the D2 receptors on the receiving cells, and those cells eventually react by reducing the number of D2 receptors. Drug researchers hypothesize that it is this change that creates a craving for cocaine: once the receptor level drops, more dopamine is needed for the user even to feel "normal."

Like cocaine use, stress can also increase the dopamine levels and apparently cause a reduction in the D2 receptors. Earlier research by Nader's team at Wake Forest showed a connection between stress and a tendency to abuse cocaine.

The current study also obs erved differences in the time it took for the D2 receptors to return to normal levels once cocaine use ended. Monkeys that used only for one week had only a 15 percent reduction in D2 receptors and recovered completely within three weeks.

But monkeys that used for a year averaged a 21 percent reduction in D2 receptors. Three of those monkeys recovered within three months, but two of those monkeys still had not returned to their baseline D2 levels after one year of abstinence.

Lack of recovery was not related to initial baseline D2 levels. The study suggests that "other factors, perhaps involving other neurotransmitter systems, mediate the recovery of D2 receptor function."

(Source: Eurekalert)
'"/>




Related medicine news :

1. Obesity And Overweight Linked To Definite Cancer Risk
2. Definite Genetic Link Between Diabetes And Obesity Established
3. 3 –D Image of Influenza Virus – A Definite Breakthrouh
4. Dog Owners Definitely Healthier
5. MMR- Autism- Bowel Problems Connection To Be Investigated
6. Is There a Connection between Hearing loss and High-speed Dental Tools?
7. Studies Find Connection Between Acid Reflux And Esophageal Cancer
8. Connection between alcohol consumption and suicidal tendencies
9. Autism Connected to Improper Connections in Brain Cells
10. The Genetic Connection in Fatal Breast Cancers
11. A New Research Explores Connection Between Emotionality And Alcoholism
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:2/8/2016)... ... February 08, 2016 , ... ... be speaking on how healthcare companies can use newly released government data on ... of a population and intervene and capture the value they create to succeed ...
(Date:2/8/2016)... , ... February 08, 2016 , ... ... only four states in the U.S. require dental technicians to be certified or ... the dental industry, NADL created the “What’s In Your Mouth?” campaign to inform ...
(Date:2/7/2016)... ... February 07, 2016 , ... HealthSmart ... employers and organizations with the tools and information to lower the costs, and ... cut the cost of providing employee healthcare benefits by as much as 22%:, ...
(Date:2/6/2016)... ... , ... US Sports Camps is proud to sponsor the Bay Area Disc ... non-profit leaders, ultimate organizations, and coaches from around the US. The theme for this ... Director of Youth and Education, describes this year YUCC as “an important conversation we ...
(Date:2/6/2016)... ... February 06, 2016 , ... Research ... treatment helps to reduce the frequency and level of relapse. , ... Healthy Identity and Purpose,” will explore the critical tasks of the recovery phase ...
Breaking Medicine News(10 mins):
(Date:2/8/2016)... , February 8, 2016 ... new report published by Allied Market Research titled, ... Opportunities and Forecasts, 2014-2020", estimates the world synthetic ... Nucleotide synthesis and sequencing technology segment would continue ... and software tools segment, collectively, held around half ...
(Date:2/5/2016)... HILL, N.C. , Feb. 5, 2016  Despite ... has been slower than other industries to embrace Big ... come with utilization. On the medical side, organizations have ... improve everything from clinical trials to adherence. ... research from benchmarking firm Best Practices, LLC, Big Data ...
(Date:2/5/2016)... , Feb. 5, 2016  Syneron Medical ... aesthetic device company, announced today that William ... North America, is scheduled to participate in the ... Conference on February 11, 2016 in ... allow institutional investors to meet with the Mr. ...
Breaking Medicine Technology: