Significant Role of Receptor Coupling in the Neuropeptide-Induced Alterations of Macrophage Cytotoxicity

Although in 1975 (Hughes et al., 1975) the year of discovery of the endogenous opiates, great expectations accompanied the research of these peptides, our knowledge regarding the central and peripheric effects of these compounds remain incomplete and superficial. Presumably the unexpected difficulties are due partly to the fact that the “secret” of the complex function of the opiate receptors has not been revealed, and on the other hand, some smaller peptide hormones derived from the large precursor molecules and displaying various biological effects could always confuse the interpretation of the essential processes.