Regulation of central cholecystokinin recognition sites by guanyl nucleotides.
Guanyl nucleotides affected the binding of radiolabeled cholecystokinin (CCK) octapeptide to rodent cortical binding sites. Micromolar quantities of a stable GTP analogue, guanylyl-imidodiphosphate (GppNp), resulted in a plateau where binding was decreased by 30%. In the presence of 25 microM GppNp, binding analysis revealed a decrease in affinity (increase in KD), without an apparent effect on the maximal number of binding sites. Ki values for CCK-related peptides shifted up to 1.6-fold. The rate of peptide association decreased by threefold, and the rapid component of peptide dissociation increased. The collective data suggest that a class of central CCK binding sites is linked to nucleotide regulatory proteins. The evidence is discussed with regard to multiple receptor populations and to possible interconversions between receptor types.
Wennogle
L
L
Research Department, CIBA-GEIGY Corporation, Summit, NJ 07901.
Wysowskyj
H
H
Steel
D J
DJ
Petrack
B
B
D000818:Animals; D001665:Binding Sites / Q000187:drug effects; D002540:Cerebral Cortex / Q000378:metabolism*; D002772:Cholera Toxin / Q000494:pharmacology; D006160:Guanosine Triphosphate / Q000031:analogs & derivatives*; D006165:Guanylyl Imidodiphosphate / Q000494:pharmacology*; D007700:Kinetics; D051379:Mice; D012844:Sincalide / Q000378:metabolism*; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D010566:Virulence Factors, Bordetella; D006165:Guanylyl Imidodiphosphate; D006160:Guanosine Triphosphate; D002772:Cholera Toxin; D012844:Sincalide