[Roles of calcitonin gene-related peptide family in pain and opioid tolerance].

The calcitonin gene-related peptide (CGRP) family mainly includes CGRPα, CGRPβ, adrenomedullin, calcitonin and amylin. The members of CGRP family and their receptors are widely distributed in the central and peripheral nervous systems. Studies show that members of CGRP family such as CGRP and adrenomedullin play important roles in the transmission of nociceptive information. At spinal level, CGRP promotes the transmission of nociceptive information, spinal morphine tolerance, migraine, inflammatory pain and neuropathic pain. At superspinal level, CGRP suppresses the transmission of nociceptive information. Adrenomedullin is a pain-related neuropeptide which has recently been demonstrated. It facilitates the transmission of nociceptive information and is involved in the development and maintenance of opioid tolerance. The involvement of amylin and calcitonin in pain is not clear yet.