Team IDs brain circuit involved in drug’s antidepressant effect
Finding could lead to development of a new, safer way to rapidly treat depression
SAN ANTONIO (Dec. 21, 2015) — At its best, the drug ketamine relieves depression within two hours and its beneficial effect on patients may last a week. At its worst, ketamine, the party drug “Special K,” is addictive and may send recreational users into hallucinations and delusions. Some have experienced disorientation that they call the “K-hole.”
Because of the potential for misuse and addiction, explained researcher Daniel Lodge, Ph.D., of The University of Texas Health Science Center at San Antonio, “You have a novel, highly effective treatment for depression, but you can’t give it to people to take at home or on a routine basis.”
Antidepressants usually take at least two weeks to show any effect in the patients they help, and not all patients benefit. If a drug were fast-acting and provided sustained relief from depression, the risk of suicide among patients would be reduced.
The problem with ketamine is that the drug acts on receptors located throughout the brain, making it difficult to control its effects.
Finding an answer
“The idea is, if one part of the brain contributes to the beneficial effects of ketamine, and another part contributes to its abuse and effects such as hallucinations, now we can come up with medications to target the good part and not the bad,” said Flavia R. Carreno, Ph.D., lead author of the study.
Identifying this mechanism now gives scientists a target, Dr. Lodge explained. “The next step is finding a drug that interacts selectively with it. And we have some ideas how to do that.”
The study was described Dec. 1 in Molecular Psychiatry, the psychiatric journal most cited by scientists.
The study is supported by National Institute of Mental Health grants to Dr. Lodge, associate professor of pharmacology, and Alan Frazer, Ph.D., professor and chairman of pharmacology in the School of Medicine. A research grant from the Institute for Integration of Medicine and Science and the School of Medicine at the UT Health Science Center also contributed to the collaboration between the Frazer and Lodge labs.
Dr. Carreno is a research instructor in Dr. Frazer’s laboratory.
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