And they said their experiments in mice may point the way to better drugs in humans. "Our approach addresses primarily chronic pain," said Hanns Zeilhofer of the University of Zurich in an e-mail. He said analgesics such as aspirin can cause stomach ulcers, while opioids such as morphine make patients sleepy and are addictive. Zielhofer's idea was to find a way to trick the body into intercepting pain signals before they cause havoc in the brain. "We know that normally the spinal cord acts as filter for pain signals. It prevents most of the pain signals from reaching the brain, where pain becomes conscious," said Zeilhofer, whose study appears in the journal Nature. Read more at: http://news.yahoo.com/s/nm/20080116/hl_nm/pain_mice_dc;_ylt=An6KxEk.emDG9aNQK2umgIoQ.3QA