Discrimination between CCK receptors of guinea-pig and rat brain by cyclic CCK8 analogues.
The properties of high affinity CCK8 binding sites of guinea-pig and rat brain cortex were compared using [3H]pCCK8. Large differences were observed, with the KD value being significantly higher in the rat (KD = 1.25 nM) than in guinea-pig brain (KD = 0.18 nM). Both sites exhibited different specificities for various CCK8 analogues, the selectivity factors KI rat/KI guinea-pig varied from 0.9 for CCK4 to 64 for cyclic CCK8-related compounds. Significant differences in the inhibition of [3H]pCCK8 binding by monovalent and nucleotides cations were also observed. These results could be explained by a difference in receptor environment or by a species difference in the proportion of CCK8 receptor-subtypes.
Durieux
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C
Département de Chime Organique, U 266 INSERM, UA 498 CNRS, Faculté de Pharmacie, Paris, France.
Pham
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H
Charpentier
B
B
Roques
B P
BP
D000818:Animals; D001667:Binding, Competitive; D002414:Cations, Monovalent; D002540:Cerebral Cortex / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000494:pharmacology; D006165:Guanylyl Imidodiphosphate / Q000494:pharmacology; D007700:Kinetics; D008297:Male; D011817:Rabbits; D051381:Rats; D011919:Rats, Inbred Strains; D011949:Receptors, Cholecystokinin / Q000187:drug effects / Q000378:metabolism*; D012844:Sincalide / Q000031:analogs & derivatives* / Q000378:metabolism*; D013045:Species Specificity
D002414:Cations, Monovalent; D011949:Receptors, Cholecystokinin; D006165:Guanylyl Imidodiphosphate; D006160:Guanosine Triphosphate; D012844:Sincalide