http://www.abc.net.au/catalyst/stories/2351893.htm video on webpage above. Programme: Catalyst, ABC TV 4 September 2008 Transcript of program also on above page.
Dr Kennaway: We thought that we understood how the brain clock worked, but we had no idea each cell actually contained all the requirements for keeping time, for keeping 24 hour time. Narration: And that has revolutionised our understanding of how the body clock - or should we say body clocks - really work. It begins with light - which resets the brain clock each morning. It then sends the hormonal messages that help keep all the other body clocks in synchrony. Dr Kennaway: I'm just, I really am in awe of it, because it's, every organ system is ticking away. Our muscles, our pancreas, our liver, our skin, our bowels, our kidneys. Pause. What that then makes possible is for the organs to plan what's going to happen next. So in the case of the liver, it can prepare for the next meal by sending some enzymes up, to help digest the food or metabolise glucose. And so it's all a very highly coordinated system of preparation for the next event. It's all been set up several hours before by this clock system. Narration: At 9pm, my brain secretes melatonin - preparing for sleep. body temperature falls. and the whole cycle starts again. At least, that's what's supposed to happen. But what if your master clock is faulty? Well, there's a growing realisation it can drive you crazy. The drummer for this weekend rock band is psychologist Dr Greg Murray. Dr Murray: More and more data has come in to support the idea that a vulnerability or some sort of deregulation in the body clock is a primary cause for mood disorders. Depression and bipolar disorder. ............. Then you'll see a very strange thing. Twenty-four hours, no sleep. The next day, the person had a sleep period, but the next day again, twenty-four hours no sleep. At this point, the person suffered a manic episode and was hospitalised and left the study. ............ Narration: In a landmark if odd looking study, he put these mice on shift work. Dr Kennaway: Well, what we find is that after just four weeks of shiftwork they become glucose intolerant and they were also insulin intolerant. And these are the precursors for developing diabetes. Narration: The reason? It turns out, the clocks in their muscles aren't ready to take up glucose from food during sleeping hours. ............ Narration: But surely people who work nights long term adjust? Well, other new research from the Centre for Sleep Research in Adelaide shows no, they never do. Unless you live somewhere like an oil rig, where all light can be excluded, you continue to make melatonin at night, and cortisol in the day. The trouble is, for most of us, that simple burst of sun on the way home is enough to reset the brain clock. Dr Kennaway: So the brain clock keeps ticking properly and getting reset, but the food and the activity is resetting the other organ clocks. This is bad, because now you've got a conflict between the brain and liver, pancreas, muscle. And that's where we see that people are likely to increase their risk of, of metabolic disease. ............
