Pressure-independent arteriolar rarefaction in hypertension.
To assess the role of pressure in the arteriolar rarefaction associated with hypertension, we studied microvascular density in a hindquarters muscle (cremaster) of rats, 8 wk after coarctation (n = 8) or sham-coarctation (n = 10) of the abdominal aorta. To document the level of arterial pressure in hindquarters vascular beds of similar rats 8-9 wk after initial surgery, we implanted femoral arterial catheters under anesthesia and, 2-5 days later, we measured conscious femoral arterial pressures in coarcted [93 +/- 4 (SE) mmHg; n = 7] and sham-coarcted (110 +/- 3 mmHg; n = 4) rats. The cremaster muscle microcirculation was examined after fixation and Microfil infusion at in vivo pressures. The density of distal third- to fourth-order arterioles was lower by 19% (P = 0.03) in coarcted (1.37 +/- 0.06 mm/mm2) than in sham-coarcted (1.69 +/- 0.11 mm/mm2) rats. We conclude that pressure-independent mechanisms are involved in the arteriolar rarefaction accompanying hypertension.
Boegehold
M A
MA
Department of Medicine, West Virginia University, Morgantown 26506.
Johnson
M D
MD
Overbeck
H W
HW
D000818:Animals; D001017:Aortic Coarctation / Q000473:pathology / Q000503:physiopathology; D001160:Arterioles / Q000473:pathology*; D001794:Blood Pressure; D002339:Carotid Arteries / Q000503:physiopathology; D005263:Femoral Artery / Q000503:physiopathology; D006614:Hindlimb; D006973:Hypertension / Q000473:pathology* / Q000503:physiopathology; D009132:Muscles / Q000098:blood supply; D051381:Rats; D011919:Rats, Inbred Strains; D014699:Venules / Q000473:pathology