Cholecystokinin in vivo reduces binding to rat hypothalamic beta-adrenergic sites.
Intraperitoneal injection of sulfated cholecystokinin octapeptide (CCK-8; 10 micrograms/kg) resulted in an increase in the IC50 for isoproterenol (4.2 microM to 23.3 microM) in displacing 1 nM 3H-dihydroalprenolol binding to rat hypothalamic membranes. 3H-p-Aminoclonidine binding was also lower in membranes prepared from CCK-treated rats, but the decrease was not statistically significant. In vitro, CCK(1-100 nM) had no effect on either alpha- or beta-adrenergic binding or on the 5'-guanylylimidodiphosphate modulation of binding. The results indicate that CCK does not act directly upon adrenergic receptors, but may reduce beta-adrenergic affinity through indirect means.
D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D003000:Clonidine / Q000031:analogs & derivatives / Q000378:metabolism; D004082:Dihydroalprenolol / Q000378:metabolism; D006165:Guanylyl Imidodiphosphate / Q000494:pharmacology; D007031:Hypothalamus / Q000378:metabolism*; D007545:Isoproterenol / Q000494:pharmacology; D007700:Kinetics; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000378:metabolism*; D012844:Sincalide / Q000494:pharmacology*
D011943:Receptors, Adrenergic, beta; D006165:Guanylyl Imidodiphosphate; D004082:Dihydroalprenolol; C016986:apraclonidine; D007545:Isoproterenol; D012844:Sincalide; D003000:Clonidine