Sydney, Apr 8 (IANS): A major discovery could open the way to more effective treatment of severe pain with the help of morphine, says a study.

Morphine is an extremely important pain killer, but has side-effects, such as developing tolerance to it and increased sensitivity to pain. How this occurs has remained a mystery, until now.

A team from the University of Colorado (US) and University of Adelaide (Australia), has linked pain killing drugs' side-effects to an immune receptor's activation in the brain, causing an inflammatory response, the journal Proceedings of the National Academy of Sciences reported.

(Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process).

Researchers have also shown how this receptor can be blocked, paving the way to the development of new drugs to boost morphine's potency while easing many of its problematic side-effects, said a university statement.

"Because morphine is considered to be such an important drug in the management of moderate to severe pain in patients right around the world, we believe these results will have far-reaching benefits," said study co-author Mark Hutchinson, ARC Research Fellow in the University of Adelaide's School of Medical Sciences.

Hutchinson's team, including University of Adelaide colleague Andrew Somogyi, professor conducted studies in mice to validate the work done at the University of Colorado by the teams of Hubert Yin and Linda Watkins.

"For some time it's been assumed that the inflammatory response from morphine was being caused via the classical opioid receptors," said Hutchinson.