http://chronicfatigue.about.com/b/20...algia-pain.htm

From the article:

Manipulating Memories of Pain

The enzyme researchers are targeting is called PKMzeta. They say it deals with long-term memory storage in several regions of the brain and also affects how pain is processed by specialized nerves (nociceptors) in an area called the spinal cord dorsal horn (SCDH.) PMKzeta helps for connections between neurons, building pathways that activate when you experience new pain.

By blocking PKMzeta in rats, scientists were able to reverse both the pain-processing abnormality in the SCDH and hypersensitivity to movement across the skin (called mechanical allodynia, which is common in fibromyalgia.)

They concluded that PKMzeta is responsible for maintaining persistent pain and could be lead to a new type of drug for chronic pain. If so, this could finally be a drug that treats the cause of pain instead of merely covering it up.