دواء جديد لمعالجة اضطراب الساعة البيولوجية في السفر

دواء جديد لمعالجة اضطراب الساعة البيولوجية (الرياض)

لندن - (ي.ب.أ) :

    اقترب علماء بريطانيون وأميركيون من انتاج دواء جديد لمعالجة الاضطراب الناتج عن الرحلات الجوية الطويلة.

ونقلت صحيفة "الديلي ميل" البريطانية أن التجارب التي أجراها العلماء على الفئران قضت على الاعتقاد السائد الذي كان يشير إلى أن الساعة البيولوجية البشرية التي تتحكم بها منطقة معينة من الدماغ تعرف بالنواة الفوق تصالبية تطلق نبضات كهربائية للتحكم بنمط النوم. وظهر أنها تطلق النبضات الكهربائية عند الغسق (أول الليل) وتكف عن العمل طوال الليل ثم تعود إلى العمل عند بزوغ الفجر.

وأشار العلماء إلى أن هذا الاكتشاف قد يقود إلى معالجة الأمراض الناتجة عن اختلال الساعة البيولوجية مثل السرطان والزهايمر أو المشاكل التي يواجهها المسافرون والاشخاص الذين يعملون في الليل. ويتمتع الجسم بنظام توقيت داخلي يعرف بالنظام اليومي وهو يساعد على تبيان وقت تناول الطعام والنوم والاستيقاظ وغيرها من الوظائف الجسدية.

وتتحكم دورة الليل والنهار جزئياً بهذا النظام.إذاً قد يؤدي تغيير المنطقة الزمنية أو العمل حتى ساعة متأخرة ليلاً،إلى الإخلال بحسّ الوقت في الجسم لأن توقيت التعرض للنور يتغير.وتتحكم منطقة في الدماغ تقع فوق سقف الفم بالساعة البيولوجية عند الإنسان والثديات .

وقد أظهرت التجارب التي أجريت على الفئران أن النواة الفوق تصالبية تحتوي على نوعين مختلفين من الخلايا، وواحدة منها فقط تتحكم بالنظام اليومي أو الساعة البيولوجية.

ويعمل في هذه الخلايا "الساعة" مورثة تدعى "بير 1" بينما لا تعمل في الخلايا الأخرى. واشار العلماء إلى أن هذه الاكتشافات قد تساعد على انتاج دواء جديد للتحكم بالساعة البيولوجية يساعد على التعافي من الاضطرابات الناتجة عن الرحلات الطويلة.

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A cure for jet lag? Scientists identify brain cell which keeps us awake

By Daily Mail Reporter
Last updated at 11:04 PM on 10th October 2009

The discovery of the brain cell which determines our sleep patterns could pave the way for the introduction of a pill to beat jetlag

A pill that cures jet lag is a step closer today, after scientists discovered how signals from the brain control our biological clocks.

Tests on mice suggested the human body clock - controlled by a region of the brain called the suprachiasmatic nuclei - does not constantly fire electrical pulses to regulate our sleeping patterns, as was previously thought.

Instead, it fires at dusk and remains inactive during the night, then stirring back to life at daybreak.

The British and American team, whose research is published in the journal Science, say it could lead to treatments for illnesses that are influenced by the body clock, such as cancer and Alzheimer's, as well as perking up frequent flyers or nightshift workers.

The body has a built-in time-keeping system, known as a circadian rhythm, that helps us keep track of when it's time to eat, sleep, wake up and perform other body functions.

This system is partly governed by the cycle of day and night.

Changing time zones or working the late shift can throw off the body's sense of timing because it changes the timing of our exposure to light.

In humans, as with all mammals, our body clock is controlled by a part of the brain, located above the roof of the mouth.

But new experiments on mice has found for the first time that  the suprachiasmatic nucleus or (SCN), contains two very different cells.

Only one of these fires our circadian rhythm, or 24-hour body clock.

These 'clock' cells express a particular gene called per1 while the 'non-clock' cells don't.  

Dr Hugh Piggins, of the University of Manchester, and colleagues say their findings could help develop new drugs to tune the daily clock and aid recovery from long haul flights.

'The aim would be to develop a drug that specifically targets the per1 cells.' said Dr Piggins.

'The SCN is located very deep in the brain and difficult to get at. You could not carry out these experiments on humans.

'This is the first time SCN cells have been looked at on the basis of genes and we discovered there are two very distinct types.

'But what is interesting is that there could also be per1 genes in other parts of the brain which could completely change our knowledge of this mysterious organ.'

The research may also advance efforts to treat diseases influenced by the circadian system including cancer, Alzheimer's disease and mood disorders.

Co-researcher Professor Daniel Forger, a mathematician at the University of Michigan, said: 'Knowing what the signal is will help us learn how to adjust it, in order to help people.

'We have cracked the code, and the information could have a tremendous impact on all sorts of diseases that are affected by the clock.'

The circadian system also affects hunger, digestion, urine production, body temperature and blood pressure.

For example, it is normally in tune with local time, so we feel hungry in the morning and sleepy at night.

Major time changes upset this rhythm, often leaving travellers sleepy in the day and wide awake at night.

The researchers found that during the day, SCN cells expressing per1 sustain an electrically excited state but do not fire.

Dr Piggins explained: 'We discovered that per1 cells are coding the time of day by being silent, which is the opposite of previous expectations.

'Before researchers would have believed that these neurons were silent because they were dead or damaged, but they are alive and well and working in an unusual manner.

'SCN clock cells in the brain have special properties to allow them to survive in unusual states.

'It is the cells that do not make per1 that behave in the conventional way.'

Study co-author Casey Diekman, a doctoral student in Prof Forger's lab, said: 'The old theory was that the cells in the SCN which contain the clock are firing fast during the day but slow at night.

'But now we have shown that the cells that actually contain the clock mechanism are silent during the day, when everybody thought they were firing fast.'

Dr Piggins said the findings 'force us to completely reassess what we thought we knew about electrical activity in the brain's circadian clock.'

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How to reset your bodyclock

by FELICITY WARNER, femail.co.uk

Tired: the time change could make you feel sleepy, say experts

Most of us are probably delighted at the thought of the extra hour in bed we'll have this weekend - thanks to the clocks going back.

But health experts say that, for many people, the sneaky lie-in that signals the end of British Summer Time is not as good for your health as it first appears.

Instead the changeover can cause havoc with sleep patterns, warns Dr Chris Idzikowski, director of the Sleep Assessment Advisory Service.

'Across the population as a whole, doctors notice marked problems for up to a week in the nation's sleep health each time the clocks change,' he says.

'Everyone has their own biological rhythm which fluctuates according to the season, and controls our sleep patterns,' he explains.

This biological clock, known as the circadian rhythm, is set primarily by the sun's light.

This explains why most of us start to feel sleepy when it gets dark and we wake up again when the sun comes out.

'But some people have more extreme body clock settings than others,' he says. 'For these people the changeover can cause bouts of temporary insomnia and a disruption to their normal routine because it takes longer for their body clocks to adjust.'

To help beat the problem, Dr Idzikowski advises setting the alarm clock half an hour earlier for a few days and then getting out of bed quickly.

'Waking up fast, exercising and eating and making maximum use of any daylight around helps our body clocks to adjust more quickly,' he says.

'Within a week you should have adjusted.'

If you are experiencing problems in dropping off to sleep there are several other steps you can take.

Follow a night time wind down routine such as taking a warm bath followed by a milky drink in bed and half an hour reading before turning the light out.

Ensure your bedroom is dark and quiet and try to eat sleep inducing foods for supper such as lettuce and avocado.

If you don't like milky drinks try chamomile or lime blossom tea.

For The Sleep Assessment and Advisory Service provides advice and sleep management programmes. Call 0845 1300 933 or click here for more information

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How to get a good night's sleep

As stress levels rise because of the ever-increasing pace of modern life, more and more people are suffering from insomnia.

At least a third of the population has trouble sleeping, and research has shown even minor sleep disturbances will cause daytime sleepiness and performance problems.

But if you have tried everything and still can't get a good night's sleep, don't give up.

Dr Chris Idzikowski, who runs the Sleep Assessment and Advisory Service and has spent 25 years researching sleep problems, says understanding your biological clock is crucial.

Here, we look at the reasons behind insomnia - and how to beat it

• How to diagnose your problem
  

  One of the best things you can do, and which I have used successfully for years with patients, is to keep a sleep diary to identify your sleep/awake pattern. This will help you understand what kind of sleep problem you have.

Create a diary in a notebook, using a horizontal line for each night. Start with 9pm at one end and 9am at the other, and mark each hour along the line.

Every morning, record what happened during the night: what time you went to bed, when you started to try to sleep, what time you think you went to sleep, when you woke and so on. Do this for two weeks.

You will then be able to see whether you have a delayed sleep time, habitually wake too early, are getting up regularly to go to the toilet, or are lying awake worrying.

• The night owl: can't sleep till early hours
  

Those who go to bed progressively later and later, then feel drowsy and unrefreshed when it's time to wake up, could have a problem with their biological clock failing to reset itself in the mornings. Instead, the 24-hour body clock is still set for night-time sleep.

As the day progresses, 'night owls' feel more and more alert - a state which is maintained throughout the evening.

Solution: It is possible to adjust your internal clock by exposing yourself to light and darkness at appropriate times.

Too much light towards the end of the day tends to make your body clock run later, making you go to sleep late and wake up later in the morning.

If you want to train yourself to get to sleep earlier, avoid bright lights in the evening. Keep lighting as low as possible, or perhaps try candlelight.

You also need to expose yourself to light first thing in the morning so that you will wake up properly and therefore fall asleep earlier that night.

You could try keeping the curtains open to get the benefit of the early light, or fling the curtains open as soon as you wake.