DRUG ADDICTION LINKED TO PROTEIN

A GROWTH promoting protein in the brain may be partly responsible for
Parkinson's disease, drug addiction and schizophrenia, scientists said
yesterday.

The protein, Brain Derived Neurotrophic Factor (BDNF) was thought to be
needed simply for the proliferation, maturation and survival of nerve cells.

But a team of French researchers has found it also boosts levels of a
receptor molecule called D3 which allows neurones to respond to dopamine.

Dopamine is a key chemical which enables neurones to communicate with one
another. Faults in the dopamine message system are believed to be involved
in brain disorders, including Parkinson's and schizophrenia, as well as
drug addiction. The scientists, led by Olivier Guillin from the Unite de
Neurobiologie et Pharmacologie Moleculaire in Paris, conducted experiments
with rats genetically engineered to provide a "model" of Parkinson's disease.

They found evidence that a reduction in BDNF levels leads to fewer D3
receptors. Further studies revealed BDNF is needed for the normal increase
in D3 production that occurs shortly after birth. They also discovered BDNF
in rats affects their response to levodopa, a compound from which neurones
produce dopamine.