(Hypertension. 2001;37:894.)
© 2001 American Heart Association, Inc.
Scientific Contributions |
Abnormal Renal Vascular Responses to Dipyridamole-Induced Vasodilation in Spontaneously Hypertensive Rats
From the Hypertension Research Laboratory, Alton Ochsner Medical Foundation, New Orleans, La.
Correspondence to Edward D. Frohlich, MD, Alton Ochsner Distinguished Scientist, Alton Ochsner Medical Foundation, 1516 Jefferson Highway, New Orleans, LA 70121.
The objective of this study was to determine whether
there were differences in hemodynamic responses of
different vascular beds to systemic administration of
dipyridamole between spontaneously hypertensive (SHR)
and normotensive Wistar-Kyoto (WKY) rats. To this end, systemic
hemodynamics and organ blood flows (using labeled
microspheres) were determined in conscious rats before and 10
minutes after dipyridamole (4
mg · kg-1 · min-1)
infusion. In both the normotensive and hypertensive rats, the
dipyridamole infusion reduced arterial
pressure by 
20 mm Hg, associated with a decreased total
peripheral resistance and an increased cardiac output.
Renal blood flow decreased significantly in SHR after
dipyridamole but remained unchanged or increased
slightly in the WKY rats. There were no other differences in regional
hemodynamics, including those of brain, liver, skin,
and muscle, between the WKY and SHR. Antihypertensive treatment
completely restored normal renal vascular response to
dipyridamole. Previous reports had demonstrated an
abnormal coronary hemodynamic response of the
SHR. Our data demonstrate that, as with coronary
hemodynamics, hypertension selectively induced
alterations in renal vasculature. These findings may be of importance
in identifying the earliest hemodynamic evidence of
developing hypertensive nephrosclerosis.
Key Words: hypertension • renal vasculature • dipyridamole • regional hemodynamics