Calcitonin gene-related peptide promotes mechanical nociception by potentiating release of substance P from the spinal dorsal horn in rats.
In vitro superfusion with capsaicin (5 X 10(-7) M) of slices of the dorsal half of the rat spinal cord produced a significant increase in a release of immunoreactive substance P (iSP). Calcitonin gene-related peptide (CGRP: 10(-6) M) significantly potentiated the capsaicin-induced release of iSP. On the other hand, when CGRP (5 nmol/rat) was intrathecally injected, the peptide produced a significant hyperalgesia to mechanical noxious stimuli (pinching the hind paw), but aversive responses and potentiation of substance P-induced aversive responses were never observed. These findings suggest that in the rat spinal dorsal horn, CGRP potentiates the release of substance P from the primary afferent terminal and promotes the transmission of nociceptive information induced by mechanical noxious stimuli.
D000818:Animals; D015740:Calcitonin Gene-Related Peptide; D002211:Capsaicin / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D066298:In Vitro Techniques; D008297:Male; D009479:Neuropeptides / Q000494:pharmacology*; D009619:Nociceptors / Q000187:drug effects*; D010146:Pain / Q000503:physiopathology*; D010147:Pain Measurement; D010812:Physical Stimulation; D051381:Rats; D011919:Rats, Inbred Strains; D013116:Spinal Cord / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D013373:Substance P / Q000378:metabolism* / Q000494:pharmacology
D009479:Neuropeptides; D013373:Substance P; D015740:Calcitonin Gene-Related Peptide; D002211:Capsaicin