THE MYSTERY OF GOING UNDER

Anaesthetic is one of the world's most widely used drugs—doctors now have a clearer understanding of how it works

- Helen Foster

I remember my anaesthetist putting the cannula in my hand and saying, “time for your gin and tonic.

” I recall his ginger beard and patterned socks, but from then, nothing — despite the fact that, apparently, I was wheeled down the corridor to the operating theatre chatting away. I woke up an hour later with a nonessential part of my body missing.

The fact that I not only don't recall the cuts that removed it, but also anything about the procedure, even before they officially knocked me out, is one of the remarkable things about anaesthetic. “The long standing theory of anaesthesia was that it put the body to sleep, it’s what the anaesthetist tells you and it’s quite a comforting thought, but it's not quite true; after all we can be easily wakened from sleep,” explains Professor Bruno van Swinderen from The University of Queensland. “We therefore knew other things must be happening as well.”

In 2018, he found out what one of these things was. He discovered that the common anaesthetic propofol actually affects the movement of a protein in the brain. This protein is part of the process your brain cells (neurons) use to talk to each other. If it’s gone, so too is their ability to communicate.

“Our brain has 100 billion neurons and a trillion points of chemical communication and the likelihood is that many of these are impaired by general anaesthetic causing the brain to lose what's called synaptic coordination across these billions of different points,” says Professor Van Swinderen. “This not only causes you to lose consciousness, but also lose behavioural responses, the sensation of pain and the ability to form memories, triggering the type of short-term memory-loss that you experienced.”