Article: Happy rats give a clue to drug addiction

[~lostgurl~]

Happy rats give a clue to drug addiction

27 April 2007
NZ Herald

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Rats are helping scientists to understand the mechanisms of drug addiction. A surprise finding in rats has given scientists a clue to understanding drug addiction in people. A single dose of morphine was found to lower the rats' inhibitions, even after the drug left their systems.

The painkiller blocked the brain's ability to strengthen connections, or synapses, that reduce reward or pleasure, researchers from Brown University in Providence, Rhode Island, reported in the journal Nature. "What we have found is that the inhibitory synapses can no longer be strengthened 24 hours after treatment with morphine, which suggests that a natural brake has been removed," said Julie Kauer, a professor of molecular pharmacology, physiology and biotechnology at Brown.

She said the finding added to growing evidence of a link between learning and addiction and may help in developing drugs to treat addiction.
By shutting off the natural ability to strengthen connections that inhibit pleasure, the brain may be learning to crave drugs.

Professor Kauer said the brain had two kinds of neurons - those that excited nerve connections and those that inhibited or depressed them.
"If inhibition is reduced, you get runaway excitability," she said.

- REUTERS

http://www.nzherald.co.nz/topic/stor...ectid=10436321