Preserved endothelium-dependent but impaired beta-adrenergic relaxation of the resistance vessels in experimental renal failure.
Chronic renal failure is associated with increased cardiovascular morbidity and reduced arterial elasticity. Only little information is available on the functional effects of uraemia on resistance arteries. Therefore, we studied the influence of renal failure on rat small mesenteric vessels. The responses of arterial rings were investigated in a Mulvany myograph 6 weeks after 5/6 nephrectomy or sham operation. The subtotal nephrectomy resulted in a 1.9-fold elevation of plasma urea nitrogen but was without significant effect on blood pressure. Endothelium-dependent relaxations, largely mediated via arterial K(+) channels, were preserved in the resistance vessels of uraemic rats. Endothelium-independent vasorelaxations, mediated via exogenous nitric oxide and the opening of ATP-sensitive K(+) channels, were also unchanged. However, the responses induced by isoprenaline were slightly reduced, indicating impaired relaxation via beta-adrenoceptors in experimental renal failure.
Jolma
Pasi
P
Department of Pharmacological Sciences, Medical School, University of Tampere, Tampere, Finland.
Kalliovalkama
Jarkko
J
Tolvanen
Jari-Petteri
JP
Kööbi
Peeter
P
Kähönen
Mika
M
Saha
Heikki
H
Pörsti
Ilkka
I
D000818:Animals; D004730:Endothelium, Vascular / Q000503:physiopathology*; D066298:In Vitro Techniques; D008297:Male; D008638:Mesenteric Arteries / Q000503:physiopathology*; D051381:Rats; D011921:Rats, Inbred WKY; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D051437:Renal Insufficiency / Q000503:physiopathology*; D014655:Vascular Resistance; D014664:Vasodilation / Q000502:physiology*
D011943:Receptors, Adrenergic, beta