Evidence for renal vascular remodeling in angiotensin II-induced hypertension.
OBJECTIVE
To determine whether 'slow pressor' hypertension from systemic angiotensin (Ang II) infusion was associated with renal vascular structural remodeling of the renal resistance vessels and glomerulus.


METHODS
Ang II (4.5-10 ng/kg per min) or vehicle was infused for 10 days. Renal resistance vascular lumen changes were assessed at 10 days as changes in renal pressure flow and pressure-glomerular filtration rate (GFR) and pressure-Na+ excretion in maximally dilated, isotonically perfused kidneys.


RESULTS
Low-dose, initially subpressor Ang II infusion for 10 days increased conscious arterial pressure by 27 mmHg compared to vehicle-infused rats (140 +/- 7 and 113 +/- 2 mmHg, respectively). There was no change in the pressure-flow relationship but the slope of the pressure-GFR relationship was reduced in the rats treated with Ang II. These changes are consistent with equal and opposite pre-and post-glomerular effects (i.e., increased pre-glomerular vessel resistance and reduced post-glomerular vessel resistance) and reduced glomerular ultrafiltration coefficient. There was also a significant reduction in pressure-dependent Na+ excretion.


CONCLUSIONS
Slow pressor Ang II-induced hypertension was associated with apparent pro-hypertensive changes in the kidney involving pre/post-glomerular vessel remodeling as indicated by an apparent reduction in pre-glomerular lumen dimensions, a reduced glomerular filtration capacity and a reduction in the pressure natriuresis relationship.
Edgley
Amanda J
AJ
Department of Physiology, Monash University, Victory, Australia. amanda.edgely@med.monash.edu.au
Kett
Michelle M
MM
Anderson
Warwick P
WP
D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D021461:Animals, Outbred Strains; D005919:Glomerular Filtration Rate / Q000502:physiology; D006977:Hypertension, Renal / Q000139:chemically induced / Q000503:physiopathology*; D007678:Kidney Glomerulus / Q000098:blood supply / Q000502:physiology; D008297:Male; D009318:Natriuresis / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012079:Renal Circulation / Q000502:physiology*; D012964:Sodium / Q000378:metabolism; D014662:Vasoconstrictor Agents / Q000494:pharmacology*
D014662:Vasoconstrictor Agents; D000804:Angiotensin II; D012964:Sodium