Bradykinin Receptor‐Mediated Cyclic GMP Formation in a Nerve Cell Population (Murine Neuroblastoma Clone N1E‐115)

A clone of murine neuroblastoma (N1E‐115) was shown to have functional receptors for the nonapeptide bradykinin. These receptors mediated a large, rapid (about 1 min to peak) and calcium‐dependent increase in cyclic GMP. The median effective concentration (EC₅₀) averaged 1.4 nM. In addition, this event was inhibited by quinacrine, 5,8,11,14‐eicosatetraynoic acid, and nordi‐hydroguaiaretic acid, suggesting involvement of phospholipase A₂ with subsequent formation of lipoxygenase metabolites of arachidonic acid. [³H]Bradykinin binding to intact cells, investigated under conditions nearly identical to those used in the cyclic GMP assay, yielded binding sites with K_Ds of 0.83 pM, 1.0 nM, and 4.9 nM with respective B_max values of 12, 160, and 250 fmol/10⁶ cells. Apparently, the cyclic GMP response was associated with the binding site in which the K_D= 1.0 nM. Peptide analogs of bradykinin stimulated cyclic GMP with EC₅₀s nearly identical to their respective K_Ds determined in binding assays with [³H]bradykinin, thus providing evidence for receptor specificity of this response. This finding of a biochemical response of bradykinin promises to make N1E‐115 cells a convenient model system for study of neuronal bradykinin receptors.