Two University of Adelaide pharmacologists working with one the world's leading neuroscientists have helped pave the way for the development of new pain-killing drugs that are not addictive.

Professor of Clinical Pharmacology at the University of Adelaide, Paul Rolan, and postdoctoral fellow Dr Mark Hutchinson are part of a combined US and Australian research team which has made a breakthrough in revealing how opioid drugs such as morphine both relieve pain and also cause addiction.

The Adelaide scientists and senior colleagues at the University of Colorado, including world glia and pain expert Dr Linda Watkins, have isolated in animal models the effect that morphine has on the brain's immune cells, known as glia, and also on nerve cells (neurons).

Glial cells heighten nerve pain such as sciatica by exciting the neurons that transmit pain signals. While morphine deadens pain by acting at nerve synapses, it also activates glial cells, worsening the drug's side effects, such as drowsiness, tolerance and addiction.

The scientists tested a new drug called AV411 that blocks morphine's effects on glia but not on neurons, resulting in effective pain relief without the side effects of addiction. AV411 is being developed by Avigen Inc., a Californian biopharmaceutical company.

Vice President of Research & Development at Avigen, Dr Kirk Johnson, says the company is working in collaboration with Dr Hutchinson and Dr Watkins from the University of Colorado as well as Professor Paul Rolan from the University of Adelaide.

"Currently, AV411 is in clinical trials at the Royal Adelaide Hospital for neuropathic pain and we look forward to exploring this molecule in opioid withdrawal," Dr Johnson said.

"Doctors prescribe morphine for pain relief but opioids come with the potential for addiction or abuse," Dr Hutchinson says. "Our tests shows that by blocking morphine's effects on glial cells, it stops cravings for the drug."

These pre-clinical findings were published in the prestigious international journal Science.

The Director of the National Institute on Drug Abuse in the United States, Dr Nora Volkow, says the research "helps pave the way toward developing new, potent, non-addictive medications".