Characterization of beta 1- and beta 2-adrenoceptor subtypes in the rat sinoatrial node and stellate ganglia by quantitative autoradiography.
We characterized beta-adrenoceptors in rat sinoatrial node (SA) and stellate ganglia by incubating consecutive tissue sections with [125I]iodocyanopindolol, with or without the beta 1-selective (CGP 20712A) or the beta 2-selective (ICI 118,551) antagonists, followed by quantitative autoradiography. In the stellate ganglia, ICI 118,551 displaced more than 90%, and CGP 20712A less than 5%, of the binding sites. CGP 20712A displaced about 50% of the binding sites in the SA, and about 65% in the rat atria. The SA has a high percentage of beta 2-adrenoceptors and the stellate ganglia contains almost exclusively beta 2-adrenoceptor binding sites, implicating beta 2-adrenoceptors in the control of heart rate in the rat.
Saito
K
K
Unit on Preclinical Neuropharmacology, National Institute of Mental Health, Bethesda, MD 20892.
Torda
T
T
Potter
W Z
WZ
Saavedra
J M
JM
D000818:Animals; D001345:Autoradiography; D001667:Binding, Competitive; D005728:Ganglia, Sympathetic / Q000378:metabolism*; D020120:Iodocyanopindolol; D008297:Male; D010869:Pindolol / Q000031:analogs & derivatives / Q000378:metabolism; D011433:Propranolol / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011943:Receptors, Adrenergic, beta / Q000032:analysis / Q000145:classification*; D012849:Sinoatrial Node / Q000378:metabolism*
D011943:Receptors, Adrenergic, beta; D020120:Iodocyanopindolol; D011433:Propranolol; D010869:Pindolol