Rhodopsin family

   Biogenic amine

   Peptide

   Chemokine

   Base and nucleoside

   Lipid

     Arachidonylglycine

     Bile acid

     Cysteinyl leukotriene

     Free fatty acid

     HETE and oxoETE

     Leukotriene

     Lysophosphatidic acid

     Lysophosphatidylinositol

     Lysophosphatidylserine

     Oleoylethanolamide

     Prostaglandin

     Prostacyclin

     Sphingolipid

     Thromboxane

   Vision

   Others

 Secretin receptor family

 Adhesion receptor family

 Metabotropic glutamate receptor family

 Frizzled / Smoothened family

 Others