Structure-activity relationships of novel peptides related to the antiarrhythmic peptide AAP10 which reduce the dispersion of epicardial action potential duration

We report the first study on short peptide structure-activity relationships (SAR) for the antiarrhythmic peptide AAP10 and its putative receptor. Synthetic improvements on the natural antiarrhythmic peptide AAPnat (H-Gly-Pro-Hyp-Gly-Ala-Gly) isolated from bovine atria led us to the synthesis of our lead molecule AAP10 (H-Gly-Ala-Gly-Hyp-Pro-Tyr-NH2) which reduces dispersion of epicardial potential duration and acts antiarrhythmically in isolated rabbit hearts. The aim of our study was to elucidate structure-activity relationships for AAP10 based on Langendorff experiments and molecular modeling. Mutation of the amino acid sequence led to 11 different peptides which were tested analogous to the lead molecule. Among these new synthetic peptides various including the cyclopeptide cAAP10RG, cyclo[CF3C(OH)-Gly-Ala-Gly-Hyp-Pro-Tyr] showed promising activities. (supported by the DFG and Koln-Fortune)