TEENAGE BRAIN 'MORE SENSITIVE TO COCAINE'

The adolescent brain may be more sensitive to addictive drugs such as
cocaine and amphetamines than either the adult or newborn, according
to a study published yesterday.

The work may pave the way to a better understanding of how the
adolescent human brain adapts to such drugs, and provide clues into
changes in the brain that result from addiction.

Scientists at Thomas Jefferson University in Philadelphia and
colleagues reported the work in the Journal of Neuroscience.

Prof Michelle Ehrlich and Dr Ellen Unterwald found a greater increase
in a protein in the part of the adolescent mouse brain called the
striatum, following chronic exposure to drugs than they did in either
very young mice or adults. The protein, called Delta FosB, plays a
role in regulating the way genes are used. Earlier research by other
scientists had shown increased amounts of Delta FosB in adult brains
following chronic exposure to psychostimulant drugs.

This "molecular adaptation," said Prof Ehrlich, could be significant.
"An increase in this protein may be important because it could also
affect other molecules that could lead to long-lasting changes in the
brain in response to psychostimulant drugs."The implications are that
there is an increased adaptation in the younger brain than in the
older brain to these drugs.

However, the effects of the increased protein activity is not
known.

Prof Ehrlich said: "Does this make them more prone to self-administer
psychostimulants, meaning these mice could be a model of addiction?
Does this make them more prone to hyperactivity?

"Are they more tolerant of higher doses of medication? These questions
are relevant to addiction and to therapeutic use of these medications
in these age groups."