Peripheral mechanism of hyperalgesia--sensitization of nociceptors.

The peripheral mechanism of hyperalgesia is considered to be the result of nociceptor sensitization. As possible agents causing nociceptor sensitization, bradykinin, histamine, prostaglandin (PG)s, protons and nerve growth factor are evaluated with respect to their release into the injured tissue, their sensitizing potencies. Whether blocking these agents suppresses sensitization was also evaluated. In addition, the intracellular mechanisms by which bradykinin, histamine and PGs cause sensitization are reviewed.