Scientists in Shanghai may have discovered a way to turn cocaine addiction on and off through a switchlike protein.

Cocaine affects the brain by increasing the level of dopamine, a neurotransmitter that plays important roles in many brain functions, including the feeling of reward and pleasure.

The drug works by inhibiting proteins that reabsorb dopamine, causing it to build up and leading to a "high".

Zhou Jiawei, the lead researcher of the team from the Shanghai Institutes for Biological Sciences under the Chinese Academy of Sciences, said that as addiction is being formed, a protein known as a dopamine transporter, or DAT, moves from inside the neuron to the cell's surface.

"We've found that the key difference lies in DAT's location in the brain," Zhou said.

"A countermove would block the migration so that the development of the addiction may be put off."

The team believes the key to blocking addiction lies in VAV2, a small protein that acts as a molecular switch to regulate the migration of DAT.

The discovery of VAV2's role may hold the key to cocaine rehabilitation efforts, according to the scientists, although other types of drug addictions would require different solutions.

A paper about their discovery was published on July 7 on the website of New York-based journal Nature Neuroscience.

The team reported that mice show diminished behavioral response to cocaine when the gene for their VAV2 protein was made ineffective.

For humans, "although gene removal is ethically questionable, ways can be designed to suppress the gene through medication," Zhou said.

An estimated 17 million people around the globe use cocaine, according to the World Drug Report 2015 by the United Nations Office on Drugs and Crime. In 2013, its use directly resulted in 4,300 deaths.

The maintenance of dopa-mine levels is essential for a variety of important brain functions, and it is also associated with diseases of the nervous system, including Parkinson's disease.

The proteins

DAT is a protein that transports dopamine. As addiction develops, the location of DAT moves from inside the neuron to the cell's surface.

VAV2 is a small protein that acts as a switch to regulate the migration of DAT.