Cerebral blood flow regulation: vascular resistance adjustments in the circle of Willis.
Continuous measurements of systemic blood pressure (BP), cerebral perfusion pressure and CBF were accomplished in the cat during transient hypertension, hypercapnia and bilateral carotid artery occlusion. From these measurements resistance values in the circle of Willis and in the cerebral arteries distal to the circle were calculated. The results indicate that the arteries of the circle of Willis and the arteries distal to the circle of Willis dilate and contract independently.
D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure; D002340:Carotid Artery Diseases / Q000503:physiopathology*; D002415:Cats; D002560:Cerebrovascular Circulation / Q000187:drug effects; D002941:Circle of Willis / Q000187:drug effects / Q000503:physiopathology*; D004837:Epinephrine / Q000494:pharmacology; D006935:Hypercapnia / Q000503:physiopathology; D006973:Hypertension / Q000503:physiopathology*; D009638:Norepinephrine / Q000494:pharmacology; D014655:Vascular Resistance
D000804:Angiotensin II; D009638:Norepinephrine; D004837:Epinephrine