UC Santa Barbara researchers have found that the impaired brain function and learning difficulties that are caused by cocaine addiction can be treated and potentially cured.
UCSB scientists Karen Szumlinski, Tod Kippin and Osnat Ben-Shahar have been researching cocaine addiction in the Department of Psychological & Brain Sciences at UCSB. The research group is particularly interested in the region of the brain known as the prefrontal cortex, where most of the decision-making processes and behavior and impulse control are located.
Szumlinski and her team found that as a test animal went into drug withdrawal, there was a second resurgence in craving for the drug after the initial withdrawal. The glutamate receptors in the prefrontal cortexes of these animals were not functioning properly and the rats were having difficulty disassociating the cues that they had tied to the drugs with getting a high. The team found that a drug that stimulates glutamate receptors could help undo learning impairment in rats with simulated cocaine addiction. The rats could then let go of their addiction and the craving would subside.
A key point that the team was initially puzzled over was the revival of cravings for the drug after several months of abstention. Studies on the subject rats found that less than a month after the initial withdrawal, the animals were craving the drug again, even with their brief lifespan of less than two years. This led to Kippin theorizing about the glutamate receptors, and the team testing the drug to stimulate the receptors and their subsequent findings.
Szumlinski described the large amount of literature on the subject of addiction and the effects on the brain, and that the team looked at the effects of withdrawal due to the work that had already been done on the subject.
“We focused on these metabotropic receptors because we had drugs that we knew were working to block drinking in our drinking studies, we knew what doses to give intracranially,” Szumlinski said.
This helped give the scientists a general direction to start to work towards. According to Szumlinski, the next step for the team is to find out what other effects the addiction and the withdrawal have on the brain with regards to the learning impairment.
“We want to know what enzyme downstream is really important to addiction,” Szumlinski said.
The team hopes to find which behavioral enyzmes are changing in concert with the receptors and get a better idea of what the causes of the withdrawal and resurgence are so that they can be better treated.
Their final goal is to find a treatment for these learning impairments and through that, assist addicts in resisting a relapse after several months of abstention, which the team calls “incubating.”
