Chugging an entire can of Sprite isn't that different from swallowing a lump of wasabi—at least as far as our nerve cells are concerned. New research reveals that all of the pent up carbon dioxide in carbonated beverages turns on a protein called TRPA1—the same one activated by other spicy condiments, including mustard oil and horseradish. To confirm TRPA1's role, researchers added a CO2-rich solution to mouse and human cells. Cells with the TRPA1 gene showed more activity in response to the bubbly than did cells without it, the team reports  today in The Journal of Neuroscience. As for why we enjoy fizzy drinks if they cause pain, the authors speculate that it may be because carbonated drinks slow bacteria growth. Or maybe it's just that doing anything masochistic makes us look macho.
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