Chronic or persistent pain is a major health problem. With prevalence ranging from one in five in young population to almost one third to one-half in older people as well as with the disability, loss of income, depression associated with unrelieved pain, the impact is significant. Pain has often been regarded merely as a symptom that serves as a passive warning signal of underlying disease process.
However, there is accumulating evidence that transmission of nociceptive signals after injury has a rapid and sustained impact on the physiological environment at a number of levels. These influences commence in the periphery with the release of various neurotransmitters leading to peripheral sensitization which is not only responsible for increased sensitivity to both mechanical and thermal stimulus at innocuous (allodynia) and noxious (hyperalgesia) levels but leads to Central sensitization…
