title: Renal ischemic injury affects renal hemodynamics and excretory functions in Sprague Dawley rats: involvement of renal sympathetic tone.
abstract: The role of renal sympathetic nerves in the pathogenesis of ischemic acute renal failure (ARF) and the immediate changes in the renal excretory functions following renal ischemia were investigated. Two groups of male Sprague Dawley (SD) rats were anesthetized (pentobarbitone sodium, 60 mg kg(-1) i.p.) and subjected to unilateral renal ischemia by clamping the left renal artery for 30 min followed by reperfusion. In group 1, the renal nerves were electrically stimulated and the responses in the renal blood flow (RBF) and renal vascular resistance (RVR) were recorded, while group 2 was used to study the early changes in the renal functions following renal ischemia. In post-ischemic animals, basal RBF and the renal vasoconstrictor reperfusion to renal nerve stimulation (RNS) were significantly lower (all p < 0.05 vs. control). Mean arterial pressure (MAP), basal RVR, urine flow rate (UFR), absolute and fractional excretions of sodium (U(Na)V and FE(Na)), and potassium (U(K)V and FE(K)) were higher in ARF rats (all p < 0.05 vs. control). Post-ischemic animals showed markedly lower glomerular filtration rate (GFR) (p < 0.05 vs. control). No appreciable differences were observed in urinary sodium to potassium ratio (U(Na)/U(K)) during the early reperfusion phase of renal ischemia (p > 0.05 vs. control). The data suggest an immediate involvement of renal sympathetic nerve action in the pathogenesis of ischemic ARF primarily through altered renal hemodynamics. Diuresis, natriuresis, and kaliuresis due to impaired renal tubular functions are typical responses to renal ischemia and of comparable magnitudes.
authors.affiliation: Department of Cardiovascular and Renal Physiology and Pharmacology, School of Pharmaceutical Sciences, Universiti Sains Malaysia, Minden, Penang, Malaysia. ibraheem_muhammed@yahoo.com
authors.forename: Ibrahim M
authors.initials: IM
authors.lastname: Salman
authors.forename: Munavvar A
authors.initials: MA
authors.lastname: Sattar
authors.forename: Nor A
authors.initials: NA
authors.lastname: Abdullah
authors.forename: Omar Z
authors.initials: OZ
authors.lastname: Ameer
authors.forename: Mun F
authors.initials: MF
authors.lastname: Yam
authors.forename: Gurjeet
authors.initials: G
authors.lastname: Kaur
authors.forename: Md Abdul
authors.initials: MA
authors.lastname: Hye Khan
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Johns
mesh_terms: D000818:Animals; D006439:Hemodynamics; D007668:Kidney / Q000098:blood supply* / Q000294:innervation* / Q000473:pathology / Q000503:physiopathology; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology*; D013564:Sympathetic Nervous System / Q000503:physiopathology*