Study of cocaine addiction reveals targets for treatment

February 13, 2013
UCSB study of cocaine addiction reveals targets for treatment
This shows a summary of cocaine-seeking behavior (lever-presses) during 30 minute sessions conducted on Days 3 and 4 of withdrawal (Test1 and 2, respectively) from daily high amounts of IV cocaine. When tested across days, vehicle-induced (VEH) controls exhibit a reduction in cocaine-seeking, indicating extinction. In contrast, rats infused intracranially into the ventromedial prefrontal cortex (vmPFC) with antagonists for mGluR5 (MTEP PreRx) or mGluR1 (JNJ PreRx) prior to Test 1 failed to show this learning. Similarly, rats injected intracranially with the mGluR1 blocker following Test 1 (to influence memory consolidation processes) also failed to exhibit learning. These data indicate that mimicking a cocaine-induced deficit in mGluR1/5 function within this frontal cortical region results in persistent cocaine-seeking behavior, reflecting a deficit in learning and memory processes. Credit: University of California - Santa Barbara

Scientists at UC Santa Barbara are researching cocaine addiction, part of a widespread problem, which, along with other addictions, costs billions of dollars in damage to individuals, families, and society.

Laboratory studies at UCSB have revealed that the diminished and learning impairment that result from can be treated—and that learning can be restored.

Karen Szumlinski, a professor in the Department of Psychological & Brain Sciences at UCSB, and her colleagues Osnat Ben-Shahar and Tod Kippin, have worked in the field of addiction for many years. Senior author of a paper on this topic published recently in The Journal of Neuroscience, Szumlinski is particularly interested in the part of the brain called the prefrontal cortex, where the process of "executive function" –– or decision-making –– is located. This area is involved in directing one's behavior in an appropriate manner, and in controlling behavior.

With her research team, Szumlinski discovered that a drug that stimulates a certain type of glutamate receptor –– when aimed at the prefrontal cortex—could restore learning impairment in rats with simulated cocaine addiction.

"Needless to say, this (the prefrontal cortex) is one of the last parts of the brain to develop, and, of relevance to our students, continues to develop through about age 25 to 28," said Szumlinski.

Szumlinski explained that in the prefrontal cortex there seems to be "hypo-frontality," or reduced functioning, in drug addicts, as well as in patients with a range of neuropsychiatric diseases, including schizophrenia, depression, and attention deficit disorder.

Szumlinski calls the prefrontal cortex a late-developing brain area that is critical for making proper decisions, and inhibiting behavior. "You damage this brain region and you lose the ability to self-regulate, you make impulsive decisions like engaging in risky sexual behavior or drug-taking, you basically go off the deep end in terms of function," she said. "So we were very much interested in how drugs of abuse impact the prefrontal cortex, given that human drug addicts show deficits in this brain area when you put them into a scanner. They show hypo-activity." She said this hypo-activity, or hypo-frontality, might relate to a neurotransmitter that scientists know is involved in exciting the brain.

A key question, according to Szumlinski, is this: "Was that hypo-frontality there in the first place, and that's why they became an addict; or did the drugs change their prefrontal cortext, to cause it to become hypo-functioning and thus they're not able to control their drug use? You can't parse that out in humans. So that's why we turn then to animal models of the disorder, and we do have this rat model that we use in the paper."

Szumlinski pointed out a key difficulty in the development of treatments for addiction: There is little money targeted to the study of this disease. Hence, in addition to studying the mechanisms that are involved, she is joining forces with researchers who study other neurological diseases that are well-funded, to help find cures. She hopes that government approval of new drugs for these other diseases would eventually make the drugs available for clinical trials to study their effects on cocaine addiction.

Szumlinski cited statistics, calculated by scientists M.K. Bird and A.J. Lawrence of Australia, indicating that addiction can cost up to 3.5 percent of gross domestic product in Western countries, equaling $485 billion in the U.S. in 2007. In that year, addiction research received less than 2 percent of public and private funding of all cancer research.

Explore further: Unlocking a major secret of the brain: Researchers uncover crucial link between hippocampus and prefrontal cortex

Related Stories

Unlocking a major secret of the brain: Researchers uncover crucial link between hippocampus and prefrontal cortex

August 15, 2012
(Medical Xpress) -- A clue to understanding certain cognitive and mental disorders may involve two parts of the brain which were previously thought to have independent functions, according to a McGill University team of researchers ...

How the brain puts the brakes on the negative impact of cocaine

January 11, 2012
Research published by Cell Press in the January 12 issue of the journal Neuron provides fascinating insight into a newly discovered brain mechanism that limits the rewarding impact of cocaine. The study describes protective ...

Gray matter in brain's control center linked to ability to process reward

November 29, 2011
The more gray matter you have in the decision-making, thought-processing part of your brain, the better your ability to evaluate rewards and consequences. That may seem like an obvious conclusion, but a new study conducted ...

Recommended for you

Cognitive cross-training enhances learning, study finds

July 25, 2017
Just as athletes cross-train to improve physical skills, those wanting to enhance cognitive skills can benefit from multiple ways of exercising the brain, according to a comprehensive new study from University of Illinois ...

Brain disease seen in most football players in large report

July 25, 2017
Research on 202 former football players found evidence of a brain disease linked to repeated head blows in nearly all of them, from athletes in the National Football League, college and even high school.

Zebrafish study reveals clues to healing spinal cord injuries

July 25, 2017
Fresh insights into how zebrafish repair their nerve connections could hold clues to new therapies for people with spinal cord injuries.

Lutein may counter cognitive aging, study finds

July 25, 2017
Spinach and kale are favorites of those looking to stay physically fit, but they also could keep consumers cognitively fit, according to a new study from University of Illinois researchers.

Brain stimulation may improve cognitive performance in people with schizophrenia

July 24, 2017
Brain stimulation could be used to treat cognitive deficits frequently associated with schizophrenia, according to a new study from King's College London.

New map may lead to drug development for complex brain disorders, researcher says

July 24, 2017
Just as parents are not the root of all their children's problems, a single gene mutation can't be blamed for complex brain disorders like autism, according to a Keck School of Medicine of USC neuroscientist.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.