Blood pressure drug could fight addiction

Chuck Bednar for redOrbit.com – @BednarChuck
A medication already approved by the US Food and Drug Administration (FDA) to treat high blood pressure has been proven effective at stopping cocaine and alcohol addiction in rats, new research published this week in the journal Molecular Psychiatry has discovered.
Lead investigator Dr. Hitoshi Morikawa, an associate professor of neuroscience at the University of Texas at Austin, and his colleagues explained that the treatment works by effectively erasing the unconscious memories that underlie addiction. If it is proven to be effective in humans, it will be the first treatment of its kind to help combat drug use and alcoholism.
In their studies, Dr. Morikawa’s team trained rodents to associate either a black room or a white one with the use of a drug, and whenever a rat was offered a choice of going into either room, the rats almost always selected the one that they had associated with their addiction. The researchers then started giving the rats the dose of an antihypertensive drug known as isradipine.
After the medication was administered to the rodents, the rats were then presented with the same choice of rooms. While they initially still preferred the room associated with their addiction, over time that preference slowly began to fade away. When compared to the results of a control group, the findings appeared to indicate that the memories were eliminated, not just suppressed.
Using israpidine to overcome cues associated with addiction
“Isradipine is currently under clinical trial to slow the progression of Parkinson’s disease, in which dopamine neurons in the midbrain slowly die,” Dr. Morikawa told redOrbit via email. He noted that this was “originally driven by studies… at Northwestern University showing that isradipine prevents death of dopamine neurons in rodent model of Parkinson’s disease.”
Dr. Morikawa explained that he and his colleagues set out to see if the ion channels blocked by isradipine, known as L-type calcium channels, could do more than kill dopamine neurons. This type of neuron is essential for learning the environmental cues associated with rewards, and are good targets to combat addiction. Addiction’s nature involves excessive learning of such cues – cues associated with addictive drugs, such dealers or syringes.
“We were expecting/hoping that isradipine will suppress the learning of drug-associated cues,” he told redOrbit, “but the finding that isradipine also reverses/erases already acquired memory of drug-associated cues was totally unexpected. We got really excited by this not only scientifically but also because of its relevance to addiction treatment.”
“Isradipine might represent an ideal drug to treat, or cure, a critical component of addiction,” Dr. Morikawa continued, admitting that it could require higher dosages than ordinarily used to treat high blood pressure. “The key is to take isradipine, then addicts need to expose themselves to drug-associated cues while isradipine is in the brain, likely within a couple of hours after taking high dosage isradipine. The idea is that everything feels routine on that day (cocaine is good as usual, dealers look attractive as usual) but these start to look unattractive in the future.”
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