A series of mouse hybridomas that produced monoclonal antibodies reactive with Substance P was prepared in an attempt to find a surrogate NK-1 receptor. When the binding profile of one particular antibody, SubP14.36.1, was compared in a rank order plot with NK-1 receptors against various agonists and antagonists of Substance P, a high correlation was found between these two binding structures. In addition, this monoclonal antibody inhibited a functional assay for Substance P. This result indicated that the pharmacological effects of this peptide can be blocked by an antibody (Ab).