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Study: Single Cocaine Dose Triggers Surge in Brian Activity
.c The Associated Press
(May 30) - A single, small dose of cocaine triggers a week-long surge of
activity in the brain that may prime the user for addiction, scientists
report.
Researchers at the University of California at San Francisco said exposure
to the drug accelerates a molecular process that is important to the
formation of memories and underlies addiction.
Their study appears in the latest issue of the journal Nature.
The UCSF team used slices of brain tissue from mice that were given cocaine.
The samples were taken from the ventral tegmental area of the brain.
The VTA is rich in dopamine, a neurotransmitter associated with pleasure
that is normally released in small amounts as a biochemical reward to brain
cells. It also is associated with the high that cocaine induces and
subsequent drug cravings that travel neuron pathways throughout the brain.
The UCSF team reported that samples from the cocaine-treated mice showed a
chain reaction in brain cells that changed the properties of a neuron
receptor named AMPA for as long as a week, long after the obvious high is
gone.
The prolonged AMPA activity triggered the release of dopamine and left the
brain primed for more of the same, they said.
These pathways typically are used in the formation of memories and learning,
but the cocaine hijacks them, they said.
''What's so amazing is that all dopamine neurons are affected by this single
cocaine exposure,'' said Mark Ungless, the study's lead author. ''It would
have a profound effect on other areas of the brain, particularly those
involved with addiction.''
The researchers said this pathway in the brain might offer one explanation
into the biochemistry of how recovering drug addicts can relapse easily.
And, they speculated, the reaction might also apply to other addictive
substances, including nicotine and alcohol.
.c The Associated Press
(May 30) - A single, small dose of cocaine triggers a week-long surge of
activity in the brain that may prime the user for addiction, scientists
report.
Researchers at the University of California at San Francisco said exposure
to the drug accelerates a molecular process that is important to the
formation of memories and underlies addiction.
Their study appears in the latest issue of the journal Nature.
The UCSF team used slices of brain tissue from mice that were given cocaine.
The samples were taken from the ventral tegmental area of the brain.
The VTA is rich in dopamine, a neurotransmitter associated with pleasure
that is normally released in small amounts as a biochemical reward to brain
cells. It also is associated with the high that cocaine induces and
subsequent drug cravings that travel neuron pathways throughout the brain.
The UCSF team reported that samples from the cocaine-treated mice showed a
chain reaction in brain cells that changed the properties of a neuron
receptor named AMPA for as long as a week, long after the obvious high is
gone.
The prolonged AMPA activity triggered the release of dopamine and left the
brain primed for more of the same, they said.
These pathways typically are used in the formation of memories and learning,
but the cocaine hijacks them, they said.
''What's so amazing is that all dopamine neurons are affected by this single
cocaine exposure,'' said Mark Ungless, the study's lead author. ''It would
have a profound effect on other areas of the brain, particularly those
involved with addiction.''
The researchers said this pathway in the brain might offer one explanation
into the biochemistry of how recovering drug addicts can relapse easily.
And, they speculated, the reaction might also apply to other addictive
substances, including nicotine and alcohol.
