receptor (, APJ) Bradykinin receptor Bradykinin receptor B1 (, BRB1) Bradykinin receptor B2 (, BRB2) GPR15 (, GPRF) GPR25 () Subfamily A4 Opioid receptor delta Opioid receptor (, OPRD) kappa Opioid receptor (, OPRK) mu Opioid receptor (, OPRM) Nociceptin receptor (, OPRX) Somatostatin receptor Somatostatin receptor 1 (, SSR1) Somatostatin receptor 2 (, SSR2) Somatostatin receptor 3 (, SSR3) Somatostatin receptor 4 (, SSR4) Somatostatin receptor 5 (, SSR5) GPCR neuropeptide receptor Neuropeptides B/W receptor 1 (, GPR7) Neuropeptides B/W receptor 2 (, GPR8) GPR1 orphan receptor () Subfamily A5 Galanin receptor Galanin receptor 1 (, GALR) Galanin receptor 2 (, GALS) Galanin receptor 3 (, GALT) Cysteinyl leukotriene receptor Cysteinyl leukotriene receptor 1 () Cysteinyl leukotriene receptor 2 () Leukotriene B4 receptor Leukotriene B4 receptor (, P2Y7) Leukotriene B4 receptor 2 () Relaxin receptor Relaxin/insulin-like family peptide receptor 1 (, LGR7) Relaxin/insulin-like family peptide receptor 2 (, GPR106) Relaxin/insulin-like family peptide receptor 3 (, SALPR) Relaxin/insulin-like family peptide receptor 4 (, GPR100/GPR142) KiSS1-derived peptide receptor (GPR54) () Melanin-concentrating hormone receptor 1 (, GPRO) Urotensin-II receptor (, UR2R) Subfamily A6 Cholecystokinin receptor Cholecystokinin A receptor (, CCKR) Cholecystokinin B receptor (, GASR) Neuropeptide FF receptor Neuropeptide FF receptor 1 (, FF1R) Neuropeptide FF receptor 2 (, FF2R) Orexin receptor Hypocretin (orexin) receptor 1 (, OX1R) Hypocretin (orexin) receptor 2 (, OX2R) Vasopressin receptor Arginine vasopressin receptor 1A (, V1AR) Arginine vasopressin receptor 1B (, V1BR) Arginine vasopressin receptor 2 (, V2R) Oxytocin receptor () Gonadotropin releasing hormone receptor (, GRHR) Pyroglutamylated RFamide peptide receptor (, GPR103) GPR22 (, GPRM) GPR176 (, GPR) Subfamily A7 Bombesin receptor Bombesin-like receptor 3 () Neuromedin B receptor () Gastrin-releasing peptide receptor () Endothelin receptor Endothelin receptor type A (, ET1R) Endothelin receptor type B (, ETBR) GPR37 (, ETBR-LP2) Neuromedin U receptor Neuromedin U receptor 1 () Neuromedin U receptor 2 () Neurotensin receptor Neurotensin receptor 1 (, NTR1) Neurotensin receptor 2 (, NTR2) Thyrotropin-releasing hormone receptor (, TRFR) Growth hormone secretagogue receptor () GPR39 () Motilin receptor (, GPR38) Subfamily A8 Anaphylatoxin receptors C3a receptor (, C3AR) C5a receptor (, C5AR) Chemokine-like receptor 1 (, CML1) Formyl peptide receptor Formyl peptide receptor 1 (, FMLR) Formyl peptide receptor-like 1 (, FML2) Formyl peptide receptor-like 2 (, FML1) MAS1 oncogene MAS1 (, MAS) MAS1L (, MRG) GPR1 () GPR32 (, GPRW) GPR44 () GPR77 (, C5L2) Subfamily A9 Melatonin receptor Melatonin receptor 1A