Tadpole probe could revolutionise science

By Stephen Naysmith, Science Correspondent

THE humble tadpole could help treat spinal injuries, and even increase our understanding of how our bodies work.
Scientists at the University of St Andrews have been awarded an £88,000 grant towards the study of the development of the tadpole nervous system. The work could benefit under standing of the way movements are controlled in all vertebrates, including humans.

While most children learn about tadpoles' life cycles at an early age, biologists do not fully understand what goes on during their remarkable transformation into frogs.

The tadpole changes from a filter feeder, using its tail for swimming , into a carnivore that moves using its legs.

In a joint research initiative with the University of Bordeaux, the St Andrews team will study 'neural plasticity' -- how the creature's nervous system adapts to control a completely new set of physical movements.

Professor Keith Sillar, head of the university's school of biology said: 'Tadpoles changing into frogs has been an object of fascination for generations. But the way the nervous system and parts of the spinal cord change within the tadpole has never been studied before.

'During the metamorphosis there is a part of the nervous system that makes the tail wiggle and a part that makes the limbs of the frog move -- and they are both in exactly the same physical space. We can learn a lot from what happens when one network takes over from the other.'

Sillar believes the way the nervous system of the tadpole develops may ultimately provide clues to the way in which the human nervous system adapts when we learn a new skill or recover from problems such as spinal injury.

Our nervous system is not hard-wired and can in fact be very flexible. Unfortunately little is understood about how such flexibility works.

Despite the gulf in development between humans and tadpoles, there is much that is the same about our make-up, Sillar said. 'All animals with backbones share a common evolutionary past ,' he pointed out.

But while the human nervous system comprises of billions of nerve cells comm unicating in a complex fashion, a tadpole's nervous system encompasses only a few thousand, allowing it to be studied more easily. Tadpoles are also helpful to researchers as they are relatively easy to breed, and because early development takes place rapidly.

The St Andrews team have already shed light on neurosteroids -- brain chemicals that are common to frogs and humans and have spectacular powers to inhibit pain.