We have previously shown that β-endorphin (END) is contained and released from memory-
type T-cells within inflamed tissue and that it is capable to control pain (J Clin Invest 100
(1)(1997) 142). Methionine-enkephalin (MET) and Dynorphin-A (DYN) are endogenous
opioids with preference for δ-and κ-opioid receptors, respectively. Both MET and DYN are
produced and contained within immune cells. The goal of this study was to determine the
release characteristics of MET and DYN in a rat model of localized hindpaw inflammation …