Inhibition of atrial natriuretic peptide-induced cyclic GMP accumulation in the bovine endothelial cells with anti-atrial natriuretic peptide receptor antiserum

Using an antiserum raised against the purified atrial natriuretic peptide (ANP) receptor that has a disulfide-linked homodimeric structure and represents one subtype of the multiple ANP receptors, we showed that the receptor is coupled to the guanylate cyclase activation; formerly, this type of ANP receptor is not considered to be coupled to the cyclase. The specificity of the antiserum was determined by immunoblot analysis and immunoprecipitation. The anti-receptor antiserum did not compete with 125I-ANP for binding to the receptor but it lowered the affinity of the receptor. When added to bovine endothelial cell cultures, the antiserum blocked the cyclic GMP response of the cells triggered by ANP. These results indicate that the subtype of the ANP receptor recognized by the antiserum is responsible for the activation of particulate guanylate cyclase as well as the double function type receptor that has been assumed to contain both the receptor domain and the catalytic domain for cGMP synthesis on the same molecule. The presence of dissociative complexes of ANP receptor and particulate guanylate cyclase was also demonstrated by radiation inactivation analysis.