Insomnia breakthrough: Scientists discover the brain cells that age us also control sleep

Many of us go to bed early in the hope of getting our beauty sleep.

But research suggests the amount of shut-eye we get may also determine how quickly we age and how susceptible we are to disease.

A new study by Oxford University reveals the ‘internal stress’ that ages our cells and can trigger ill health also activates the neurones – nerve cells – that control sleep.

The scientists hope this will bring us one step closer to understanding the mysterious function of sleep, as well as enabling us to better treat insomnia.

Existing sleeping pills often become less effective over time and can carry nasty side effects including drowsiness while awake, hallucinations and breathing difficulties.  

The research was led by Professor Gero Miesenböck, director of the Centre for Neural Circuits and Behaviour.

Oxidative – or internal – stress occurs when there is an imbalance between free radicals and antioxidants in the body.

Free radicals are oxygen-containing molecules that can damage tissue. 

And a lack of antioxidants means this harm cannot be sufficiently prevented or reversed. 

‘It’s no accident that oxygen tanks carry explosion hazard labels: uncontrolled combustion is dangerous,’ Professor Miesenböck said. 

‘Animals, including humans, face a similar risk when they use the oxygen they breathe to convert food into energy.

‘Imperfectly contained combustion leads to “oxidative stress” in the cell. 

‘This is believed to be a cause of ageing and a culprit for the degenerative diseases that blight our later years. 

‘Our new research shows that oxidative stress also activates the neurons that control whether we go to sleep.’

To determine how sleep may affect our health, the researchers looked at fruit flies – the same insects that gave us an insight into our body clock nearly 50 years ago.

Fruit flies have a set of neurones that control their sleep patterns, with the same brain cells also being found in other animals and most likely humans. 

Past research suggests these neurones act like an ‘on-off switch’ – when the cells are active the fly is asleep and when they are inactive the insect is awake. 

Dr Seoho Song – a former graduate student in Professor Miesenböck’s laboratory and co-lead author of the study – said: ‘We decided to look for the signals that switch the sleep-control neurons on. 

‘We knew from our earlier work that a main difference between sleep and waking is how much electrical current flows through two ion channels – called Shaker and Sandman. 

‘During sleep, most of the current goes through Shaker.’

Ion channels generate and control the electrical impulses through which brain cells communicate.

‘This turned the big, intractable question “why do we sleep?” into a concrete, solvable problem,’ Dr Song said. 

‘What causes the electrical current to flow through Shaker?’

The team found the answer – published in the journal Nature – in the Shaker channel itself. 

Study author Dr Anissa Kempf and postdoctoral research scientist said: ‘Suspended underneath the electrically conducting portion of Shaker is another part, like the gondola under a hot air balloon. 

‘A passenger in the gondola, the small molecule NADPH, flips back and forth between two chemical states – this regulates the Shaker current. 

‘The state of NADPH, in turn, reflects the degree of oxidative stress the cell has experienced. 

‘Sleeplessness causes oxidative stress and this drives the chemical conversion.’ 

According to Professor Miesenböck, drugs that change the chemistry of Shaker-NADPH may be a powerful sleeping pill.

‘Sleep disturbances are very common and sleeping pills are among the most commonly prescribed drugs,’ he said.

‘But existing medications carry risks of confusion, forgetfulness and addiction. 

‘Targeting the mechanism we have discovered could avoid some of these side effects.’