text: Type-A cholecystokinin receptors in CHP212 neuroblastoma cells: evidence for association with G protein and activation of phosphoinositide hydrolysis.
  125I-Bolton Hunter-cholecystokinin octapeptide (BH-CCK8) and (-)-[3H]L-364718 membrane binding assays were used to identify and characterize cholecystokinin (CCK) receptors in CHP212 human neuroblastoma cells. The ligand binding properties of CCK receptors in these cells are similar to those found in pancreas (CCK-A sites) and differ from the predominant type of CCK binding site found in brain (CCK-B sites). The specific binding of 125I-BH-CCK8 but not (-)-[3H]L-364718 was reduced by the metabolically stable GTP analog guanosine 5'-(beta-delta-imido)trisphosphate. A substantial difference in the Bmax for the radiolabeled agonist (125I-BH-CCK8) and antagonist [(-)-[3H]L-364718] was noted. These observations are consistent with CCK receptors existing in guanine nucleotide-binding protein-coupled and -uncoupled states. Similar to its action in pancreatic acinar cells, CCK8(S) stimulated the accumulation of [3H]inositol phosphates in cells prelabeled with [3H]myo-inositol (EC50 = 3.2 +/- 0.4 nM; maximum response = 4.5 +/- 0.4 x basal). The intrinsic activity of CCK analogues in stimulating phosphoinositide hydrolysis was substantially less than their reported intrinsic activity in stimulating phosphoinositide hydrolysis in pancreatic acinar cells. The CHP212 neuroblastoma cell may serve as a useful model for the recently reported CCK-A binding site found in the central nervous system.
  
entities.text: ['CHP212 neuroblastoma cells']
entities.type: Cell
entities.entity_id: PMID-2539554_T1
entities.text: ['membrane']
entities.type: Cellular_component
entities.entity_id: PMID-2539554_T2
entities.text: ['CHP212']
entities.type: Cell
entities.entity_id: PMID-2539554_T3
entities.text: ['neuroblastoma cells']
entities.type: Cell
entities.entity_id: PMID-2539554_T4
entities.text: ['cells']
entities.type: Cell
entities.entity_id: PMID-2539554_T5
entities.text: ['pancreas']
entities.type: Organ
entities.entity_id: PMID-2539554_T6
entities.text: ['brain']
entities.type: Organ
entities.entity_id: PMID-2539554_T7
entities.text: ['pancreatic acinar cells']
entities.type: Cell
entities.entity_id: PMID-2539554_T8
entities.text: ['cells']
entities.type: Cell
entities.entity_id: PMID-2539554_T9
entities.text: ['pancreatic acinar cells']
entities.type: Cell
entities.entity_id: PMID-2539554_T10
entities.text: ['CHP212 neuroblastoma cell']
entities.type: Cell
entities.entity_id: PMID-2539554_T11
entities.text: ['central nervous system']
entities.type: Anatomical_system
entities.entity_id: PMID-2539554_T12