Enhanced release of immunoreactive CGRP and substance P from spinal dorsal horn slices occurs during carrageenan inflammation.

In vitro superfusion was used to examine the effect of inflammation on the release of immunoreactive calcitonin gene-related peptide (iCGRP) and substance P(iSP) from the dorsal horn of rats. Three hours after carrageenan, hindpaws exhibited hyperalgesia, edema, and hyperthermia. Spontaneous and capsaicin-evoked release of iCGRP and iSP were significantly increased following inflammation. The enhanced release of iCGRP and iSP in the dorsal horn may serve as a biochemical marker for the development of hyperalgesia.