New find is boost for stroke victims

Scientists discovered a neuronal signalling system that blocks the brain's ability to repair itself.

Switching off the pathway, known as GABA, improved recovery in mice that had suffered strokes.

When a stroke occurs, the brain becomes over-excited, causing large numbers of neurons to die off.

GABA is part of a natural process that tries to overcome this problem by reducing excitability levels.

But the research by US scientists showed that although the system, called "tonic inhibition", initially limited the spread of stroke damage, it persisted for too long.

SURPRISING

Over a period of weeks, the reduction in brain activity held back recovery.

"It was surprising to find that the level of tonic inhibition was increased for so long after stroke.

"There was an inflection point where the increased level eventually hindered the brain from recovering," said study leader Dr Tom Carmichael, from the University of California at Los Angeles.

By blocking off the GABA molecule in mice, it was possible to "switch off" the tonic inhibition response, said the scientists writing in the journal Nature.

The experts now believe that the findings identify a potential new target in the brain for effective stroke recovery treatments.

hnews@herald.ie