An eye on the body clock

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  An eye on the body clock

Research at Imperial College London points to photoreceptors in eye for

the control of biological clock

By Haddlesey

The latest link between light levels and biorhythms comes from

researchers at Imperial College, University of London, who have

identified two distinct tasks for the eye. The first is obvious function

of seeing and the second is what is referred to as the 'light measuring

eye' which uses special receptors to measure light levels and interact

with other areas of the body.

It has long been accepted that there is a link between light levels and

cycles and certain aspects of our physiology and theories have tended

towards a link between light and the pineal gland in the head. This

latest research explores a different area.

"This is a completely unexplored photosensory system of the eye," says

, co-director of Imperial College's Centre for

Chronobiology. "It's very unexpected and on the basis of the data that

we have, it's going to have a broad impact on very many areas of

biology, not just the regulation of the (internal) clock, but other

behavioural responses as well."

One possible benefit is the ability to adjust the physiological reaction

to jet lag or night work. "Light is the best drug we have for shifting

the biological clock. An understanding of the fundamental pathways of

using light to regulate the circadian system will give us some insight

into a finer level of manipulation," continues. ""At the moment

we've been using light rather like a hammer to hit the clock, and what

we need to do is really have a much more refined approach to using light

as a stimulus," explains. "We'll get that understanding when we

understand how light is actually perceived and passes that information

on to the clock centres."

Indications of the existence of such a system first came in 1991 but

were met with scepticism from most scientists who couldn't believe that

anything new could be discovered about the eye after so many years of

study. The results of this latest research have provided enough evidence

for Russel to publish his results and continue exploring this area.

"An understanding of this photosensory system in our own species will

ultimately tell us much about the relationship we have between light,

health and human performance," says .

There are far-reaching benefits to better understanding our 24-hour

internal cycles. For example, diseases like cancer and heart disease

might be more effectively treated by timing drug delivery. Cells in the

body divide in cycles and cancer studies have shown that if drugs are

given when the healthy cells of the gut or liver aren't dividing, then

tumour cells can be attacked with fewer side effects," he added.

 

http://www.lightseek.com/Articles/an_eye_on_the_body_clock.htm

Later,

Liz