Neuroscientists discover how valium 'calms the nerves'

Strictly embargoed until 1am Thursday 3 July 1997

Neuroscientists from the Australian National University have made a discovery that could explain how valium works on the brain to relax and calm the nerves.

The researchers, led by Professor Peter Gage from the John Curtin School of Medical Research, have shown drugs called benzodiazepines, which include valium, "damp-down" electrical activity in the brain by interfering with chemical signals exchanged by nerve cells.

The discovery, to be published on July 3 in the scientific journal Nature, could help scientists design more effective anaesthetics with fewer side effects, Prof Gage said.

"Current anaesthetics work more-or-less the same way as hitting you over the head with a club," he said. "They knock you out and you are as sick as a dog afterwards. We are lucky to have them-I wouldn't want to have lived in an age when we didn't-but we have got to go a lot further."

The neurones that make up the brain and nervous system transmit signals by releasing chemicals that are recognised by receptors on adjacent nerve cells.

Prof Gage's team showed valium enhances the effect of the body's own chemicals on a nerve receptor known as a GABA-receptor, dramatically increasing its effectiveness. This reduces electrical activity in the nerve cells.

"This discovery is so revolutionary that we sat on it for a while to make sure we were right," he said.

Once the exact interaction between the drug and the receptor has been more accurately established, other drugs may be designed that have a similar effect-possibly leading to forms of pain relief or anaesthesia that are more specific than current crude methods, Prof Gage said.

Nobody knows exactly how most drugs work on the brain despite liberal prescription worldwide by doctors and pharmacists, he said.

"How aspirin works to relieve pain in terms of its actual mechanism is still a mystery, and we know as much about acupuncture as we do about general anaesthesia in terms of how it actually works," he said.

To really understand the brain, and how different drugs affect it, Prof Gage believes scientists must look at the very small molecular events that influence individual nerve cells.

"It is clear to me that we really have to go more molecular to understand the brain," he said. "I don't know how a computer comes up with some of the things it comes up with, but you have to understand the transistor before you can understand the computer-it's the same with the brain."

For more information: Professor Peter Gage, JCSMR, Division of Neuroscience: Tel 06 249-2893, Damon Shorter, ANU Reporter: Tel 06 249-4170 20/97