Abstract: An analgesic benefit is realized by continuously supplying a peptide in vivo that activates an opioid receptor or that interferes with the binding of substance P to its receptors. The long-term, continuous provision of such a peptide can be accomplished by (a) transducing myogenic cells with DNA expressing the peptide and (b) administering the transduced myogenic cells to a patient, such that the cells continuously produce the peptide.