Effect of renal sympathetic nerve on adrenergically and angiotensin II-induced renal vasoconstriction in normal Wistar-Kyoto rats.
BACKGROUND
This study examined the effect of renal sympathetic innervation on adrenergically and angiotensin II (Ang II)-induced renal vasoconstriction in Wistar-Kyoto (WKY) rats.


METHODS
Forty-eight WKY rats were treated with either losartan (10 mg/kg/day p.o.) or carvedilol (5 mg/kg/day p.o.) or a combination of them (10 mg/kg/day + 5 mg/kg/day p.o.) for 7 days. On day 8, the rats were anaesthetized, and renal vasoconstrictor experiments were carried out. A group of rats was subjected to acute unilateral renal denervation during the acute study. Changes in the renal vasoconstrictor responses were determined in terms of reductions in renal blood flow caused by Ang II, noradrenaline (NA), and methoxamine (ME).


RESULTS
In normal animals, losartan decreased (P < 0.05) the renal vasoconstrictor response to Ang II but not to NA or ME. Carvedilol treatment, however, blunted (P < 0.05) the renal vasoconstrictor responses to Ang II and adrenergic agonists. Combination of losartan and carvedilol blunted (P < 0.05) the renal vasoconstrictor response to Ang II but augmented the responses to NA and ME (all P < 0.05). Interestingly, when denervated rats were treated with the same combination, there was a reduction (P < 0.05) in the renal vasoconstrictor responses to Ang II and adrenergic agonists.


CONCLUSIONS
Data suggest that the renal sympathetic nerve contributes to adrenergic agonist-mediated renal vasoconstrictions in normal rats. The data further indicate an interactive relationship between renin-angiotensin and sympathetic nervous systems in modulating adrenergically and Ang II-induced renal vasoconstriction in WKY rats.
School of Pharmaceutical Sciences, Universiti Sains Malaysia, Minden, Penang, Malaysia. mdapharm78@yahoo.co.uk
Mohammed H
MH
Abdulla
Munavvar A
MA
Sattar
Nor A
NA
Abdullah
Abdul Hye
AH
Khan
Kolla R L
KR
Anand Swarup
Hassaan A
HA
Rathore
Raisa N
RN
Kazi
Fathihah
F
Basri
Edward J
EJ
Johns
D058646:Adrenergic alpha-1 Receptor Agonists / Q000494:pharmacology*; D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D007668:Kidney / Q000294:innervation*; D008297:Male; D008729:Methoxamine / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology; D051381:Rats; D011921:Rats, Inbred WKY; D044140:Receptor, Angiotensin, Type 1 / Q000502:physiology; D018340:Receptors, Adrenergic, alpha-1 / Q000502:physiology; D012079:Renal Circulation / Q000187:drug effects; D013564:Sympathetic Nervous System / Q000502:physiology*; D014661:Vasoconstriction / Q000187:drug effects*
D058646:Adrenergic alpha-1 Receptor Agonists; D044140:Receptor, Angiotensin, Type 1; D018340:Receptors, Adrenergic, alpha-1; D000804:Angiotensin II; D008729:Methoxamine; D009638:Norepinephrine