Class A Rhodopsin-like

Acetylcholine

Metastin

Adenosine

Neuromedin

Adrenergic

Neuropeptide

Adrenomedullin

Neurotensin

Anaphylatoxin

Nicotinic Acid

Apelin

Olfactory

Bile Acids

Opioid

Bombesin

Opsin

Bradykinin

Orexigenic neuropeptide QRFP

Cannabinoid

Orexin

Carboxylic Acid

Orphan-A

Chemokine

Platelet activating factor

Cholecystokinin

Proadrenomedullin N-terminal peptide

Cysteinyl leukotriene

Prokineticin

Dopamine

Prostanoid

Endothelin

Proteinase-activated

Fatty acid

Purinergic

Fmet-leu-phe

Relaxin

Galanin

Releasing hormone

Glycoprotein hormone

Serotonin/5-Hydroxytryptamine

GPR37/endothelin B-like

Somatostatin

Histamine

Sugar sensing

Leukotriene B4 receptor

Tachykinin

Lysophospholipid/Lysosphingolipid

Trace amine

Melanin-concentrating hormone receptor

Transmembrane estrogen receptor

Melanocortin

Urotensin

Melatonin

Vasopressin/oxytocin

Class B Secretin-like

Class C Metabotropic glutamate/pheromone

Frizzled/Smoothened family

Putative/unclassified GPCRs

Vomeronasal receptors V1RL