This "proof-of-principle" experiment, described in the November issue of the Journal of Nuclear Medicine, "opens up a whole new, non-invasive way to study and follow transgenic or genetically engineered strains of mice that serve as animal models for human neurological diseases, such as Parkinson's and Alzheimer's disease or psychiatric diseases such as substance abuse, depression, and anxiety disorders," said Panayotis (Peter) Thanos, lead author of the paper. Studying animal models may help scientists better understand and develop treatments for the human diseases.
Thanos and his team used microPET to measure the level of "D2" receptors for dopamine -- a brain chemical associated with feelings of reward and pleasure, which has been found to play a role in drug addiction -- in the brains of normal mice and so-called knockout mice, which had been genetically engineered to lack the gene for D2. The dopamine D2 receptor has been implicated in a wide variety of neuropsychiatric disorders, including, in recent studies by Brookhaven researchers, alcoholism and substance abuse. Thus, these D2-deficient mice are important for studying human diseases.
Before the scans, each mouse was given an injection of a radiotracer molecule designed to bind to D2 receptors. The microPET scanner then picked up the signal from the tracer to show where and how much was bound in various parts of the brain. The level of the tracer indicates the number of receptors.
In the striatum, a region of the brain normally rich in D2 receptors, "deficient" mice had significantly lower levels of tracer binding compa
Contact: Karen McNulty Walsh
DOE/Brookhaven National Laboratory