Navigation Links
Subordinate monkeys more likely to choose cocaine over food
Date:4/6/2008

WINSTON-SALEM, N.C. Having a lower social standing increases the likelihood that a monkey faced with a stressful situation will choose cocaine over food, according to a study at Wake Forest University School of Medicine. More dominant monkeys undergoing the same stressful situation had fewer changes in brain activity in areas of the brain involved in stress and anxiety and were less likely to choose cocaine.

Robert Warren Gould, a graduate student in the laboratory of Michael A. Nader, Ph.D., presented the study results Sunday at Experimental Biology 2008 in San Diego. The presentation was part of the scientific program of the American Society for Pharmacology and Experimental Therapeutics (ASPET).

Male cynomolgus monkeys live in a complex social structure in which the social hierarchy is established by physical aggression and maintained by clear signals. A monkey that has established his dominance over another monkey can elicit a subordinate response with no more than a meaningful look.

The researchers exposed four dominant and four subordinate monkeys to a socially stressful situation in which an individual monkey was taken out of his home cage and placed in an unfamiliar cage surrounded by four unfamiliar animals. The monkey was physically safe, but he could see and hear the animals around him engaging in aggressive behavior.

The study was performed twice, in order to ask two different types of questions. The first concerned brain activity caused by the stressful situation. Before being placed in the unfamiliar cage, each monkey had been injected with radioactively labeled glucose. After 40 minutes, each was given a PET brain imaging examination to see which parts of the brain were most active, as determined by which parts were using the most glucose. This type of brain imaging has been used frequently in humans to determine brain activity during various activities and situations. The scan of the individual monkeys brain during the stressful situation was compared to earlier scans made when the animal had spent time simply sitting in his own familiar home cage without stress.

The brains of dominant monkeys and subordinate monkeys responded differently in both situations. In the normal situation of sitting in their home cage, subordinate monkeys displayed less activity than did the dominant monkeys in areas of the brain involved in stress and anxiety (the amygdala and hippocampus) and also in areas of the brain involved with emotional and social processing (anterior cingulate cortex).

Gould and Nader say these findings suggest monkeys that have to cope with constant, ongoing social stressors may have developed a lower level of brain activity even at rest. In the abnormal situation of being placed in an unfamiliar cage surrounded by unfamiliar and aggressively behaving monkeys, however, the subordinate monkeys showed pronounced decreased brain activity in areas of the brain involved with stress, anxiety, reward, and emotion, whereas the dominant monkeys showed increases in reward-related areas after the same situation.

In a separate part of the study, researchers looked at the effect of the stressful situation on the likelihood that monkeys would use cocaine. After the 40 minutes in the unfamiliar cage surrounded by other monkeys, each monkey could choose between pressing a lever that they knew delivered cocaine or one that they knew delivered a food reward. The subordinate monkey was more likely to choose cocaine while the dominant monkey was less likely to choose cocaine after this encounter, compared to their respective typical choices during the days preceding this encounter.

These differences in both brain activity and the likelihood of using cocaine between animals of different social rank offer clues to the social context of drug use and addiction in humans, say the researchers. Nader said, We believe this type of research can be used to identify better treatment strategies, including providing environmental enrichment, that may affect the likelihood of abusing drugs.

Its also important, he said, to understand distinct patters of neurobiological activity occurring after acute social stress that may increase the attraction to cocaine in vulnerable individuals. Understanding the brain changes associated with stress also is critical in developing treatment and prevention strategies for disorders such as anxiety and depression that can result from chronic stress.


'/>"/>

Contact: Karen Richardson
krchrdsn@wfubmc.edu
336-716-4453
Wake Forest University Baptist Medical Center
Source:Eurekalert

Related medicine news :

1. Flextronics Announces Redemption and Change of Control Repurchase Offer for Solectron 8.00% Senior Subordinated Notes and Planned Change of Control Repurchase Offer for Solectrons 0.50% Senior Convertible Notes
2. Providence Service Corporation Completes Private Placement of $70 Million of Convertible Senior Subordinated Notes
3. MQ Associates, Inc. Announces Expiration of its Tender Offers for its 12 1/4% Senior Discount Notes Due 2012 (CUSIP No. 55345RAC2) and Medquest, Inc.s 11 7/8% Senior Subordinated Notes Due 2012 (CUSIP No. 58505DAD1)
4. Progression of SIV infection in monkeys raises
5. Parasites a key to the decline of red colobus monkeys in forest fragments
6. Protein Nasal Spray Revives Sleep-Deprived Monkeys
7. AVMA Urges Outlawing Trafficking of Chimps, Monkeys and Nonhuman Primates and Pets
8. Minorities more likely to have sleep durations associated with increased mortality
9. Scientists ID Likely Culprit in Popcorn Lung
10. Pop stars more than twice as likely to die an early death
11. Smokers More Likely to Develop Dementia
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:12/2/2016)... ... ... Halfway through its partnership with First 5 LA, Western University of Health Sciences’ ... 5 years old and younger and treatment services to more than 9,100 of these ... to Western University of Health Sciences, UCLA and USC, beginning March 1, 2013, to ...
(Date:12/2/2016)... ... December 02, 2016 , ... Two years ago, Arizona State ... watched live by 1 million viewers and won numerous honors, including the region’s ... at the Walter Cronkite School of Journalism and Mass Communication are following up ...
(Date:12/2/2016)... ... ... twenty-four years, Doctors on Liens has published a directory of the top doctors ... When the company started in 1997, the directory was a single page focusing on ... ten-page directory features a vast array of medical specialists stretching from Sacramento to ...
(Date:12/2/2016)... , ... December 02, 2016 , ... Advanced Inc., a ... has appointed Jason Bice, CPA, MBA to serve as Advanced Inc.’s Chief Financial Officer, ... Inc. , Jason brings extensive financial and operational leadership experience to Advanced Inc. ...
(Date:12/2/2016)... ... 2016 , ... Center for Autism and Related Disorders (CARD) Portland today announced ... disorder (ASD) and other developmental disabilities. The group, which is being launched with the ... the opportunity to share stories and advice, seek help, and continue their education on ...
Breaking Medicine News(10 mins):
(Date:12/2/2016)... SAN FRANCISCO , Dec. 2, 2016  PipelineRx, ... clinical telepharmacy, will be offering demonstrations of its ... American Society of Health-System Pharmacists 2016 Midyear Clinical ... Las Vegas . With nearly 300 hospital ... telepharmacy services and technology designed to dramatically improve ...
(Date:12/2/2016)... On Thursday, December 1st 2016, the Prix ... and innovation in the biopharmaceutical industry at its third ... presence of Sergey Tsyb, Vice Minister of Industry and ... Natalia Sanina, First Vice Chairman of the State Duma ... National Service of Control in Healthcare, Sergey Muravev, Director ...
(Date:12/2/2016)...  Eli Lilly and Company (NYSE: LLY ... provide updated financial guidance for 2016 on Thursday, December ... on that day with the investment community and media ... The conference call will begin at 10 a.m. ET. ... live webcast of the conference call through a link ...
Breaking Medicine Technology: