Cholecystokinin receptors or CCK receptors are a group of G-protein coupled receptors which bind the peptide hormones cholecystokinin (CCK) and gastrin. There are two different subtypes CCK<sub>A</sub> and CCK<sub>B</sub> which are ~50% homologous: Various cholecystokinin antagonists have been developed and are used in research, although the only drug of this class that has been widely marketed to date is the anti-ulcer drug proglumide.

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! Protein

! Gene

! Tissue distribution

! Preferred ligand

! Function

!Mechanism

|-

| CCK<sub>A</sub> (CCK<sub>1</sub>)

|

| primarily gastrointestinal tract, lesser amounts in the CNS

| sulfated CCK >> nonsulfated CCK ≈ nonsulfated CCK

| stimulation of bicarb secretion, gall bladder emptying and inhibiting gut motility

|G<sub>q</sub>

|-

| CCK<sub>B</sub> (CCK<sub>2</sub>)

|

| primarily CNS, lesser amounts in the gastrointestinal tract

| gastrin ≈ CCK (receptor does not discriminate between sulfated and nonsulfated peptides)

| regulation of nociception, anxiety, memory and hunger

|G<sub>q</sub>/G<sub>11</sub>