latest stories:  Personal Pain  A single gene may account for
individual sensitivities   MU OPIATE RECEPTOR. This 3D model
shows the receptor's helical arms, which reach out and embrace
natural pain killers and addictive opiates alike. People with
more receptors feel less pain.  President Clinton may feel your
pain--but that doesn't mean it hurts him very much. Indeed,
people have very different tolerance levels; the same needle may
feel like a pinch to one person and an ice pick to the next.
Certainly part of how people perceive pain depends on
expectations, fears and other psychological influences. But
scientists have now gathered more evidence that pain sensitivity
has a strong physical basis as well.  "Many assume the way
people respond is voluntary. 'Just put up with it' has been a
common recommendation for years," notes George R. Uhl, the lead
researcher behind the latest results. "But now people can think
of pain as a genetically regulated problem."  Uhl and his
colleagues, Ichiro Sora and Zaijie Wang,