Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Experimental treatments for cocaine addiction may prevent relapse

27.08.2010
Doctors have used the drug disulfiram to help patients stay sober for several decades. It interferes with the body's ability to metabolize alcohol, giving a fierce hangover to someone who consumes even a small amount of alcohol.

More recently, disulfiram was shown to be effective in treating cocaine addiction as well, even though alcohol and cocaine affect the nervous system in different ways.

Now, researchers at Emory University School of Medicine have identified how disulfiram may exert its effects, and have shown that a newer drug with fewer side effects works by the same mechanism.

The results are published online this week by the journal Neuropsychopharmacology. Research assistant professor Jason Schroeder, PhD, and graduate student Debra Cooper are co-first authors of the paper, and the research also involved collaborations with P. Michael Iuvone, PhD, director of research at the Emory Eye Center, Gaylen Edwards, DVM, PhD, head of the department of physiology and pharmacology at the University of Georgia's College of Veterinary Medicine, and Philip Holmes, PhD, professor of psychology at the University of Georgia.

"Disulfiram has several effects on the body: it interferes with alcohol metabolism, but it inhibits several other enzymes by sequestering copper, and can also damage the liver," says senior author David Weinshenker, PhD, associate professor of human genetics at Emory University School of Medicine. "We wanted to figure out how disulfiram was working so we could come up with safer and potentially more effective treatments."

In treating cocaine addiction, there are several challenges: not only getting people to stop taking the drug, but also preventing relapse. Cocaine boosts the levels of several neurotransmitters, including dopamine and norepinephrine, at the junctions between nerve cells by blocking the machinery the brain uses to remove them.

Under normal conditions, dopamine is important for the sensation of pleasure produced by natural rewards such as food or sex, Weinshenker says. Cocaine "hijacks" the dopamine system, which plays a large role in addiction. Similarly, norepinephrine has a role in attention and arousal, but its overactivation can trigger stress responses and relapse, he says.

Weinshenker's team showed that disulfiram prevents rats from seeking cocaine after a break, a model for addicts tempted to relapse. At the same time, it doesn't stop them from taking cocaine when first exposed to it, or from enjoying their food.

Disulfiram appears to work by inhibiting dopamine beta-hydroxylase, an enzyme required for the production of norepinephrine. A dose of disulfiram that lowers the levels of norepinephrine in the brain by about 40 percent is effective, while doses that do not reduce norepinephrine have no effect on relapse-like behavior in rats.

To confirm that the beneficial effects of disulfiram were because of dopamine beta-hydroxylase inhibition, the researchers turned to a drug called nepicastat, which was originally developed for the treatment of congestive heart failure in the 1990s.

"Nepicastat is a selective dopamine beta-hydroxylase inhibitor that does not sequester copper or impair a host of other enzymes like disulfiram," Weinshenker says. "We reasoned that if disulfiram is really working through dopamine beta-hydroxylase, then nepicastat might be a better alternative."

Researchers at the University of Texas Medical Branch at Galveston have recently completed a Phase I safety trial studying nepicastat for the treatment of cocaine addiction in human subjects.

Weinshenker is co-inventor on a patent on the use of dopamine beta-hydroxylase inhibitors for the treatment of cocaine dependence, and could benefit from their commercialization. This has been reviewed by Emory University's Conflict of Interest Committee, and a management plan is in place.

The research was supported by the National Institute of Drug Abuse and the National Eye Center.

Reference:

J.P. Schroeder et al. Disulfiram Attenuates Drug-Primed Reinstatement of Cocaine Seeking via Inhibition of Dopamine â-Hydroxylase.

Neuropsychopharmacology, 35, page numbers TK (2010).

The Robert W. Woodruff Health Sciences Center of Emory University is an academic health science and service center focused on missions of teaching, research, health care and public service. Its components include the Emory University School of Medicine, Nell Hodgson Woodruff School of Nursing, and Rollins School of Public Health; Yerkes National Primate Research Center; Winship Cancer Institute of Emory University; and Emory Healthcare, the largest, most comprehensive health system in Georgia. Emory Healthcare includes: The Emory Clinic, Emory-Children's Center, Emory University Hospital, Emory University Hospital Midtown, Wesley Woods Center, and Emory University Orthopaedics & Spine Hospital. The Woodruff Health Sciences Center has a $2.5 billion budget, 17,600 employees, 2,500 full-time and 1,500 affiliated faculty, 4,700 students and trainees, and a $5.7 billion economic impact on metro Atlanta.

Learn more about Emory's health sciences: http://emoryhealthblog.com - @emoryhealthsci (Twitter) - http://emoryhealthsciences.org

Holly Korschun | EurekAlert!
Further information:
http://www.emory.edu

More articles from Life Sciences:

nachricht Staying in Shape
16.08.2018 | Max-Planck-Institut für molekulare Zellbiologie und Genetik

nachricht Chips, light and coding moves the front line in beating bacteria
16.08.2018 | Okinawa Institute of Science and Technology (OIST) Graduate University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

Im Focus: The “TRiC” to folding actin

Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.

Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...

Im Focus: Lining up surprising behaviors of superconductor with one of the world's strongest magnets

Scientists have discovered that the electrical resistance of a copper-oxide compound depends on the magnetic field in a very unusual way -- a finding that could help direct the search for materials that can perfectly conduct electricity at room temperatur

What happens when really powerful magnets--capable of producing magnetic fields nearly two million times stronger than Earth's--are applied to materials that...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

2018 Work Research Conference

25.07.2018 | Event News

 
Latest News

Staying in Shape

16.08.2018 | Life Sciences

Diving robots find Antarctic seas exhale surprising amounts of carbon dioxide in winter

16.08.2018 | Earth Sciences

Protein droplets keep neurons at the ready and immune system in balance

16.08.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>