Effect of AMRPs on contractions of the esophagus of Aplysia. A, Dose-dependent inhibition of the esophagus motility by GAPRFIamide. B, Dose–response relationship for the five purified AMRPs. ■, GAPRFVamide; ○, GAPRFIamide; ▵, GPPRFIamide; ⋄, GSPHFIamide; ⊞, GSPRFFamide.C, Dose–response relationship for the nine predicted AMRPs. ■, GAAPKFFamide; ⋄, GQAPRFIamide; ○, AMAPKFFamide; ▵, AAPRFFamide; ⊞, QAPRFFamide, ▪, SDPFFMamide; ♦, GAPRFLamide; ●, QAPRFIamide; ▴, LWVPGMVamide. Note that LWGPGMamide and SDPFFMamide were much less potent than the others.