title: Aortic blood flow subtraction: an alternative method for measuring total renal blood flow in conscious dogs.
abstract: We have measured total renal blood flow (TRBF) as the difference between signals from ultrasound flow probes implanted around the aorta above and below the renal arteries. The repeatability of the method was investigated by repeated, continuous infusions of angiotensin II and endothelin-1 seven times over 8 wk in the same dog. Angiotensin II decreased TRBF (350 +/- 16 to 299 +/- 15 ml/min), an effect completely blocked by candesartan (TRBF 377 +/- 17 ml/min). Subsequent endothelin-1 infusion reduced TRBF to 268 +/- 20 ml/min. Bilateral carotid occlusion (8 sessions in 3 dogs) increased arterial blood pressure by 49% and decreased TRBF by 12%, providing an increase in renal vascular resistance of 69%. Dynamic analysis showed autoregulation of renal blood flow in the frequency range <0.06-0.07 Hz, with a peak in the transfer function at 0.03 Hz. It is concluded that continuous measurement of TRBF by aortic blood flow subtraction is a practical and reliable method that allows direct comparison of excretory function and renal blood flow from two kidneys. The method also allows direct comparison between TRBF and flow in the caudal aorta.
authors.affiliation: Department of Physiology and Pharmacology, University of Southern Denmark, DK-5000 Odense, Denmark. ncfsand@dadlnet.dk
authors.forename: N C F
authors.initials: NC
authors.lastname: Sandgaard
authors.forename: J L
authors.initials: JL
authors.lastname: Andersen
authors.forename: N-H
authors.initials: NH
authors.lastname: Holstein-Rathlou
authors.forename: P
authors.initials: P
authors.lastname: Bie
mesh_terms: D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging / Q000502:physiology*; D001157:Arterial Occlusive Diseases / Q000503:physiopathology; D001562:Benzimidazoles / Q000494:pharmacology; D001713:Biphenyl Compounds; D001783:Blood Flow Velocity; D001794:Blood Pressure; D002339:Carotid Arteries / Q000503:physiopathology; D004285:Dogs; D019332:Endothelin-1 / Q000494:pharmacology; D005260:Female; D006706:Homeostasis; D012039:Regional Blood Flow / Q000187:drug effects; D012077:Renal Artery / Q000000981:diagnostic imaging; D012079:Renal Circulation / Q000502:physiology*; D015203:Reproducibility of Results; D012212:Rheology; D013382:Subtraction Technique / Q000592:standards; D013777:Tetrazoles / Q000494:pharmacology; D014463:Ultrasonography; D014655:Vascular Resistance; D014662:Vasoconstrictor Agents / Q000494:pharmacology
chemical_list: D000959:Antihypertensive Agents; D001562:Benzimidazoles; D001713:Biphenyl Compounds; D019332:Endothelin-1; D013777:Tetrazoles; D014662:Vasoconstrictor Agents; D000804:Angiotensin II; C081643:candesartan