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Prof Frederick Sachs
We would have to be very sure about a drug's toxicity
 real 28k

Prof David Worrell, John Radcliffe Hospital, UK
Venoms are being used in the treatment of high pressure
 real 28k

Wednesday, 3 January, 2001, 19:19 GMT
Spider calms the quaking heart
Grammostola spatulata Provincial Museum of Alberta
Crawly but not creepy: Tarantula venom could help the heart
Venom from the tarantula spider could help prevent a common heart condition called atrial fibrillation.


I didn't believe this was real science at first because it shouldn't be this good

Prof Frederick Sachs
Instead of beating normally and synchronously, fibrillating muscle in the heart's upper chambers (the atria) starts to quiver.

This may cause blood to pool and clot which can lead to further complications. Atrial fibrillation is thought to cause around 15% of strokes.

Now researchers at the State University of New York, US, have found a protein in the venom of certain spiders that could provide a novel drug treatment in the future.

Heart throb

"The heart contains receptors for mechanical input, which generate electrical currents," Professor Frederick Sachs told BBC News Online.

"There are about 10 billion cells in the heart and they're all excitable and they're all connected together. It's the electrical connections between them that normally synchronise the heart. Then, when there's a problem, they get unsynchronised."

The problem arises when heart tissue becomes stretched, either by disease or external trauma.

Mechanical changes in stretched heart tissue distort the receptors, generating random electrical signals, which in turn cause a chaotic twitching of the surrounding heart tissue.

Side-effects reduced

Professor Sachs and his team set out to find a chemical that would quiet the random contractions. They found the answer - in the jaws of a spider.

A small protein in the venom of the Chilean Rosehair tarantula (Grammostola spatulata) blocks the rogue transmissions, bringing the fibrillation under control. Experiments with rabbit hearts have shown that in some cases the protein completely stops fibrillation.

Interestingly, the protein only works on stretched heart muscle. Even a massive dose has no effect on normal healthy heart tissue, which could mean a reduced risk of side effects.

"It's too good to be true, I didn't believe this was real science at first because it shouldn't be this good," said Professor Sachs.

The potential for a simple drug treatment for a common heart condition has already attracted the interest of several drug companies.

The research is published in the journal Nature.

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See also:

23 Jun 00 | G-I
Disturbed heart rhythm
18 May 00 | Sci/Tech
Tarantula 'may save lives'
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