Spider venom holds promise of chronic-pain relief

Hundreds of millions of people around the world suffer from what doctors call "chronic pain".

They cannot take anasthetics like morphine because, in the long term, their bodies would develop a tolerance to them. In high-doses, pain-relief drugs can have debilitating side-effects.

But as Al Jazeera's Andrew Thomas reports from Brisbane in Australia, scientists at the University of Queensland think that spider venom could contain the secrets of effective pain relief.

"I cannot think of anything that’s as chemically complex in nature as spider venom," Institute of Molecular Bioscience researcher Glenn King, tells Al Jazeera.

"They are the most complex of any of the venomous animals." King and others are studying the compounds found in the venom of tarantulas. Within the hundreds of chemicals that make up a tarantula's venom are some that affect the nerve system.

Some block the channels that deliver pain signals to the brain while others lead to paralysis.

They believe that working out exactly which molecules do what could revolutionise treatment for sufferers of chronic pain.