April 26, 2007
Morphine Affects Brain’s Synapse Process
A U.S. study has found morphine blocks the brain's ability to strengthen inhibitory synapse connections -- an important finding for addiction therapy.
Brown University Professor Julie Kauer and colleagues found as little as a single dose of morphine could contribute to addiction. The study also supports a theory that addiction is a disease of learning and memory.
In the study, the researchers found long-term potentiation, or LTP, is blocked in the brains of rats given as little as a single dose of morphine. The drug's impact was powerful, with LTP continuing to be blocked 24 hours later -- long after the drug was out of the animal's system.
The persistence of the effect was stunning, Kauer said. This is your brain on drugs.
Kauer and her team not only recorded cellular changes caused by morphine but also molecular ones. In fact, the researchers pinpointed the very molecule that morphine disables -- guanylate cyclase. That enzyme, or inhibitory neurons themselves, would be effective targets for drugs that prevent or treat addiction.
The study by Kauer, Fereshteh Nugent and Esther Penick, appears in the journal Nature.