Angiotensin II AT1 receptors in rat superior cervical ganglia: characterization and stimulation of phosphoinositide hydrolysis.
Angiotensin II receptor number was higher in superior cervical ganglia of 2-week-old when compared to 8-week-old rats. In both young and adult rats, specific binding of [125I][Sar1]angiotensin II was displaced competitively by the AT1-receptor antagonist DuP 753 but not by the AT2-receptor competitor PD 123177. In ganglia from adult rats, DuP 753 competed with an IC50 of 113 nM. The stable guanine nucleotide GTP gamma S inhibited binding of [125I][Sar1]angiotensin II in young and adult rats by approximately 50% with IC50 values of 105 and 120 nM, respectively, suggesting that the angiotensin receptor is G-protein linked. Angiotensin II at a dose of 1 microM stimulated inositol phosphate formation 58% over control values in superior cervical ganglia from 8-week-old rats. This effect was totally blocked by 10 microM DuP 753 but not by 10 microM PD 123177. Our findings demonstrate that rat superior cervical ganglia contain AT1-type angiotensin receptors that are probably G-protein linked, and their stimulation results in increased inositol phospholipid metabolism.
Strömberg
C
C
Section on Pharmacology, National Institute of Mental Health, Bethesda, MD 20892.
Tsutsumi
K
K
Viswanathan
M
M
Saavedra
J M
JM
D000804:Angiotensin II / Q000031:analogs & derivatives / Q000378:metabolism / Q000502:physiology*; D000818:Animals; D001345:Autoradiography; D005260:Female; D019204:GTP-Binding Proteins / Q000502:physiology; D005728:Ganglia, Sympathetic / Q000378:metabolism / Q000502:physiology / Q000648:ultrastructure*; D006868:Hydrolysis; D007457:Iodine Radioisotopes; D008297:Male; D010716:Phosphatidylinositols / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D011945:Receptors, Angiotensin / Q000378:metabolism / Q000502:physiology*; D015290:Second Messenger Systems / Q000502:physiology; D013268:Stimulation, Chemical
D007457:Iodine Radioisotopes; D010716:Phosphatidylinositols; D011945:Receptors, Angiotensin; D000804:Angiotensin II; C074793:angiotensin II, Sar(1)-; D019204:GTP-Binding Proteins