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LONDON - Tarantulas and chilli peppers may not appear to have anything in common, but an encounter with either the spider or the plant can be painful.
Scientists at the University of California at San Francisco have found they use similar tactics to frighten off predators by causing pain.
The venom of tarantula Psalmopoeus cambridgei, a native species in Trinidad and Tobago, contains toxins that trigger the same pain receptor on nerve cells as hot chilli peppers.
Capsaicin, the main pungent ingredient in hot chilli peppers, sets it off.
"We have identified a new mechanism whereby venoms produce pain, and we have shown it is similar to one used by pepper plants to generate a similar sensation," said David Julius, a molecular biologist.
When Dr Julius and his colleagues, who reported their findings in the journal Nature, tested the venom of the spider in the laboratory on cells that contained the receptor it sparked a response, but not in the cells without the receptor.
The researchers also isolated three compounds from the spider venom.
Mice with the receptor showed signs of pain and inflammation when the compounds were applied to one of their paws.
But there was no response in transgenic mice which lacked the receptor.
- REUTERS
