Opiate receptor-mediated chemotaxis of human monocytes

The opiate peptides, D-ala-D-leuenkephalin, beta-endorphin and dynorphin, [1-13] are potent stimulators of human mononuclear cell chemotaxis. Peak responses were observed in the range of 10(-8) - 10(-11)M with activity detectable at 10(-14)M. Morphine was without effect in this assay. Incubation of cells with (-) naloxone but not (+) naloxone completely blocked activity, supporting stereospecific opiate receptor-mediated chemotaxis. Opiates and other neuropeptides are discussed as components of a network whose purpose is to integrate brain and behavioral modalities with immune function.