Dynorphin A enhances mitogen-induced proliferative response and interleukin-2 production of rat splenocytes

It has been well known that immune function is modulated by endogenous opio id peptides: beta-endorphin and enkephalins. However, the effect of dynorph in A on the immune function has not been well documented. In this study, we investigated dynorphin A in the regulation of mitogen-induced proliferatio n and and interleukin-2 (IL-2) production of rat splenocytes. The results s howed that dynorphin A 1-13 as well as dynorphin A 1-17 enhanced concanaval in A-stimulated [H-3] thymidine uptake 46-112% and IL-2 production in a dos e-dependent fashion. These effects were reversed by naloxone and norBNI, a selective kappa-receptor antagonist. Dynorphin A reduced cyclic AMP content s in spenocytes in naloxone and norBNI reversible fashion. The data suggest that dynorphin A enhanced mitogen-stimulated lymphocyte proliferation and IL-2 production via kappa-opioid receptor and cAMP pathway.