The distribution of binding sites for NTE-biotinyl-[Arg3]-substance P (SPB) was demonstrated in neonatal foreskin using a conjugate of streptavidin with horseradish peroxidase. The observed binding is reversible, and may be abrogated by either the non-peptide substance P receptor antagonist, CP-96,345, or by unlabelled substance P.
The generalized epidermal distribution and focal dermal localization of SPB binding suggest that although NK-1 receptors are abundant in human neonatal foreskin, neuromodulatory mechanisms may play a significant role in epidermal physiology.