MOLECULE CAN CURB ADDICTS' CRAVINGS

Blocking Agent Not Yet Tested In Humans

SASKATOON - A University of Saskatchewan-led team has developed an
agent that could universally block a gamut of addictions, from
nicotine to alcohol to cocaine.

But researchers don't know yet if the synthetic peptide that stemmed
addiction to nicotine and marijuana in rats is safe or effective in
humans.

In research published yesterday in the March edition of Nature
Medicine, investigators show a molecule called PTEN interacts with
receptors that in turn excite dopamine neurons --the cells responsible
for signalling pleasure.

A synthetic peptide called Tat-3L4F interrupted that interaction and
stopped rats from being addicted to both nicotine and marijuana.

Although only tested with nicotine and marijuana, Dr. Xia Zhang,
associate professor of psychiatery at the University of Saskatchewan,
said the treatment could work for a range of illicit drugs because
they all act by exciting dopamine neurons in the ventral tegmental
area of the brain.

In the study, rats were placed in a white box after receiving
injections of addictive drugs, and placed in a black box on alternate
days, when they received a placebo, or drugless, injection. Later,
researchers placed the rats between the black and white boxes and
recorded how much time they spent in each.

Rats who were addicted to nicotine or marijuana, but received the
special interfering peptide, spent equal time in the black and white
boxes, signalling they had kicked their addictions. Rats who didn't
get the peptide spent most of their time in the white boxes.