Stroke O’Clock – early morning brain blood supply

It is a well established medical fact that blood supply to the brain is at its lowest ebb in the morning – that’s not an excuse to stay in bed, but it is a factor implicated in stroke and other cardiovascular incidents.

It’s widely assumed that this has something to do with our circadian rhythms – the internal ‘body clock’ that puts us to sleep at night. But nobody knows which underlying mechanisms actually influence morning blood flow in the brain: Is the blood supply tuned into our body clock? Is it because it’s quiet and dark at night? Or is it simply because we’ve been lying down?

University of Otago physiologist Dr Philip Ainslie has received a Fast-Start Marsden grant to look into these basic mechanisms regulating blood flow to the brain – knowledge that could be important in stroke-prevention strategies.

Dr Ainslie will use sophisticated ultrasound techniques and biochemical methods on sixteen volunteers. After undergoing medical screening, and keeping a sleep diary for two weeks, the subjects will stay in bed – and awake – in the sleep-lab for thirty hours. By keeping the lighting constant, and ruling out changes in their activity levels, Dr Ainslie will be able to tell if the brain blood supply has its own body clock. He’ll also investigate the role nitric oxide, a molecule involved in the communications between cells in humans, plays in this rhythm.

The Fast-Start programme is a Marsden Fund initiative to give emerging researchers an opportunity to explore an innovative idea, developing their capabilities and helping them establish their research career.

Total Funding:    $140,000 Fast-Start
Researchers:    Dr Philip Ainslie, Department of Physiology, University of Otago, Dunedin.