Anaesthetics do more than just inducing sleep, says study

Melbourne: Scientists have found that general anaesthetics do more than simply putting people to sleep, an advance that may lead to improved drugs for surgery.

Even though general anaesthesia is one of the most common medical procedures worldwide, it remains unclear how it works, researchers said.

"We looked at the effects of propofol - one of the most common general anaesthetic drugs used during surgery – on synaptic release," said Bruno van Swinderen, Associate Professor at University of Queensland in Australia.

Synaptic release is the mechanism by which neurons – or nerve cells - communicate with each other.

"We know from previous research that general anaesthetics including propofol act on sleep systems in the brain, much like a sleeping pill," van Swinderen said.

"But our study found that propofol also disrupts presynaptic mechanisms, probably affecting communication between neurons across the entire brain in a systematic way that differs from just being asleep. In this way it is very different than a sleeping pill," he said.

According to Adekunle Bademosi, PhD student at University of Queensland, the discovery sheds new light on how general anaesthetics worked on the brain.

"We found that propofol restricts the movement of a key protein (syntaxin1A) required at the synapses of all neurons.

This restriction leads to decreased communication between neurons in the brain," Bademosi said.

The finding, published in the journal Cell Reports, contributes to understanding how general anaesthetics work, and could explain why people experienced grogginess and disorientation after coming out of surgery.

"We think that widespread disruption to synaptic connectivity - the brain's communication pathways - is what makes surgery possible, although effective anaesthetics such as propofol do put you to sleep first," van Swinderen said.