Renal functional & haemodynamic changes following acute unilateral renal denervation in Sprague Dawley rats.
OBJECTIVE
Regulation of renal function and haemodynamics are under a direct control from the renal sympathetic nerves and renal denervation produces overt diuresis and natriuresis in several mammalian species. However, the inter-related series of changes in renal function and haemodynamics following acute renal denervation (ARD) is not fully understood. Thus, we aimed to investigate and relate the changes in renal function and haemodynamics following acute unilateral renal denervation in anaesthetized Sprague Dawley (SD) rats.


METHODS
Male SD rats were fasted overnight, anaesthetized with sodium pentobarbitone (60 mg/kg ip), denervated by application of phenol to the left renal artery and maintained on an intravenous (iv) infusion of isotonic saline for 2 h. Throughout this period, six urine and plasma samples were taken at 20-min intervals to study kidney function parameters. In a different set of experiments, renal nerve stimulation (RNS) was carried out to characterize the changes in renal vasoconstrictor responses following ARD.


RESULTS
Denervated animals showed significantly (P<0.05 vs. control innervated rats) higher urine flow rate (UFR), absolute sodium excretion (UNaV), fractional sodium excretion (FENa) and glomerular filtration rate (GFR). The renal vasoconstrictor responses to RNS were significantly (P<0.05) lower in denervated rats as compared to the innervated counterparts. However, no appreciable differences were seen in the mean arterial pressure (MAP), plasma sodium (PNa), basal renal blood flow (RBF) and basal renal vascular resistance (RVR) in both innervated and denervated SD rats.


CONCLUSIONS
Natriuresis, diuresis, enhanced GFR and impaired vasoconstriction in response to RNS are typical and instant responses to ARD in SD rats. Renal sympathetic nerves serve more important role in salt and water conservation than in dynamic autoregulation of RBF under normal sympathetic tone; yet, their effects on renal haemodynamics become more evident in the presence of augmented renal sympathetic nerve activity (RSNA).
Salman
Ibrahim M
IM
Department of Cardiovascular & Renal Physiology & Pharmacology, School of Pharmaceutical Sciences Universiti Sains Malaysia, Penang, Malaysia. ibraheem_muhammed@yahoo.com
Sattar
Munavvar A
MA
Abdullah
Nor A
NA
Ameer
Omar Z
OZ
Hussain
Fathihah Basri NurJannah M
FB
Hye Khan
Md Abdul
MA
Yam
Mun Fei
MF
Rathore
Kolla R L Anand Swarup Hassaan A
KR
Kazi
Raisa N
RN
Salman
Harith M
HM
Johns
Edward J
EJ
D000818:Animals; D004231:Diuresis; D006439:Hemodynamics; D007668:Kidney / Q000294:innervation* / Q000502:physiology; D008297:Male; D019800:Phenol / Q000008:administration & dosage; D051381:Rats; D017207:Rats, Sprague-Dawley; D013563:Sympathectomy, Chemical
D019800:Phenol