Angiotensin AT2 receptors regulate cerebral blood flow in rats.
LARGE cerebral arteries have been reported to contain angiotensin receptors that are exclusively of the AT2 subtype. We measured the effect of the AT2 receptor selective ligand PD 123319 on cerebral blood flow (CBF) in rats, using laser-doppler flowmetry. PD 123319 (1-10 mg kg-1) dose-dependently inhibited the increase in CBF, when the blood pressure was increased by a norepinephrine infusion. However, PD 123319 did not alter baseline CBF at normal blood pressures. Therefore PD 123319 appears to interfere with the autoregulatory mechanisms of CBF. The participation of AT2 receptors in the regulation of CBF confirms a physiological role for this receptor subtype, and may give clues for future treatment of various cerebrovascular disorders.
Strömberg
C
C
Section on Pharmacology, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892.
Näveri
L
L
Saavedra
J M
JM
D000804:Angiotensin II / Q000378:metabolism / Q000494:pharmacology*; D057911:Angiotensin Receptor Antagonists; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D002560:Cerebrovascular Circulation / Q000187:drug effects / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D006973:Hypertension / Q000139:chemically induced / Q000503:physiopathology / Q000517:prevention & control; D007093:Imidazoles / Q000494:pharmacology; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology*; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011945:Receptors, Angiotensin / Q000187:drug effects / Q000502:physiology*; D012965:Sodium Chloride
D057911:Angiotensin Receptor Antagonists; D007093:Imidazoles; D011725:Pyridines; D011945:Receptors, Angiotensin; D000804:Angiotensin II; C073402:PD 123319; D012965:Sodium Chloride; D009638:Norepinephrine