Characteristics of 125I-Bolton-Hunter labelled cholecystokinin binding in human brain.

The high affinity binding of 125I-Bolton-Hunter labelled CCK-8 (125I-BHCCK) was studied in human brain using ligand binding and autoradiographic techniques. High levels of 125I-BHCCK binding were observed in cortex, striatum and cerebellum. In cerebellar membranes 125I-BHCCK binding was inhibited by CCK analogues with an order of potency, caerulein greater than CCK-8 greater than CCK-33 greater than gastrin 1-17 = CCK-8 non-sulphated. CCK-4 was inactive. It is suggested that in human brain 125I-BHCCK labels a population of CCK receptors similar to those observed in guinea pig brain. The properties and distribution of these receptors differ from those of rat brain.