Renal medullary blood flow and salt load in Lyon hypertensive rats.
The present work studied renal medullary blood flow (MBF) and its response to salt load in Lyon hypertensive (LH) rats to understand the mechanisms underlying the abnormal renal sodium excretion exhibited by LH rats. Experiments were conducted in uninephrectomized, anesthetized, and volume-expanded 15-week-old male LH and their normotensive (LL) controls. Under standard diet, LH rats exhibited a blunted pressure diuresis and natriuresis associated with an absence of pressure-induced increase in MBF compared to LL rats. One week of salt load (2% NaCl as drinking water) induced a significant increase in blood pressure (BP) in LH (+11 mm Hg) than in LL (+6 mm Hg) rats associated with a decrease in MBF in LH rats only (from 182 +/- 25 to 122 +/- 20 perfusion units, P < .001). Finally, despite the salt load-induced increase in pressure natriuresis, it remained significantly lower in LH than in LL rats. The results show an alteration in MBF regulation in LH rats and suggest that this abnormality may be involved in their blunted pressure natriuresis and their enhanced salt sensitivity.
Sarkis
Albert
A
Département de Physiologie et Pharmacologie Clinique, CNRS UMR 5014, Institut Fédératif de recherche Cardiovasculaire 39, Faculte de Pharmacie, Lyon, France.
Liu
Kiao Ling
KL
Lo
Ming
M
Benzoni
Daniel
D
D000818:Animals; D006973:Hypertension / Q000503:physiopathology*; D007679:Kidney Medulla / Q000098:blood supply*; D008297:Male; D009318:Natriuresis / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D012982:Sodium, Dietary / Q000009:adverse effects*
D012982:Sodium, Dietary