Different modulatory effects of ammonium ions on angiotensin vascular actions in isolated rat aortic and renal arteries

• Main Authors: Popescu Raducu I., Bild W., Ciobica A., Bild Veronica
• Format: Article
• Language: English
• Published: University of Belgrade, University of Novi Sad 2012-01-01
• Series: Archives of Biological Sciences
• Subjects: Ammonia; angiotensins; vascular smooth muscle
• Online Access: http://www.doiserbia.nb.rs/img/doi/0354-4664/2012/0354-46641202427P.pdf

In the present study, we were interested in the vascular effects of angiotensin II on perfused rings of the rat thoracic aorta and renal artery. Our results demonstrated different modulator alterations of these preparations induced by ammonium ions. Unlike the aortic rings, which exhibited only a reduction of angiotensin-induced contractility by NH4Cl, the renal artery preparations showed both activation of vasoconstriction and inhibition of vasorelaxation in the ring precontracted with phenylephrine or noradrenalin. These results are interpreted as a modulation by the ammonium ions of vascular reactions induced by the stimulation of the vasoconstrictor AT1 receptor on the one side and AT2 vasodilator receptors on the other. The potentiation of renal vasoconstriction accompanied by the reduction of angiotensin vasodilation by NH4Cl suggests the possibility of involvement from the blood flow and renal vascular tonus disturbances induced by ammonium ions during hyperammonemia of various causes.