Inhibition of angiotensin II-induced contraction by losartan in human coronary arteries

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Inhibition of angiotensin II-induced contraction by losartan in human coronary arteries. / Holmgren, Anton; Pantev, Emil; Erlinge, David; Edvinsson, Lars.

I: Journal of Cardiovascular Pharmacology, Vol. 32, Nr. 4, 1998, s. 662-664.

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TY - JOUR

T1 - Inhibition of angiotensin II-induced contraction by losartan in human coronary arteries

AU - Holmgren, Anton

AU - Pantev, Emil

AU - Erlinge, David

AU - Edvinsson, Lars

PY - 1998

Y1 - 1998

N2 - The in vitro effects of angiotensin II (Ang II) in human vessels are not well studied. The development of specific Ang II-receptor antagonists has made it possible to delineate more carefully the receptor mechanisms involved. The objective of this study was twofold: to investigate the effect of Ang II on human coronary arteries and to study the effects of angiotensin II type 1 receptor blockade with losartan. The setting was contractile experiments with ring segments of coronary arteries. We observed that Ang II is a vasoconstrictor of human coronary arteries, with a pEC50 value of 9.26 +/- 0.22 and Emax of 68.7 +/- 9.61% of potassium-induced contraction. Losartan (10-100 nM) shifted the concentration-response curve of Ang II to the right, with pEC50 values of 7.64 +/- 0.10 and 7.00 +/- 0.15, respectively (p = 0.001), demonstrating the antagonistic properties of losartan. We also noted a decreased maximal response to Ang II after incubation of losartan, with Emax of 51.1 +/- 7.08% and 41.9 +/- 4.70% (p = 0.05), respectively. In conclusion, this is the first report describing the contractile effect of Ang II and the antagonizing effects of losartan in isolated human coronary arteries.

AB - The in vitro effects of angiotensin II (Ang II) in human vessels are not well studied. The development of specific Ang II-receptor antagonists has made it possible to delineate more carefully the receptor mechanisms involved. The objective of this study was twofold: to investigate the effect of Ang II on human coronary arteries and to study the effects of angiotensin II type 1 receptor blockade with losartan. The setting was contractile experiments with ring segments of coronary arteries. We observed that Ang II is a vasoconstrictor of human coronary arteries, with a pEC50 value of 9.26 +/- 0.22 and Emax of 68.7 +/- 9.61% of potassium-induced contraction. Losartan (10-100 nM) shifted the concentration-response curve of Ang II to the right, with pEC50 values of 7.64 +/- 0.10 and 7.00 +/- 0.15, respectively (p = 0.001), demonstrating the antagonistic properties of losartan. We also noted a decreased maximal response to Ang II after incubation of losartan, with Emax of 51.1 +/- 7.08% and 41.9 +/- 4.70% (p = 0.05), respectively. In conclusion, this is the first report describing the contractile effect of Ang II and the antagonizing effects of losartan in isolated human coronary arteries.

M3 - Article

VL - 32

SP - 662

EP - 664

JO - Journal of Cardiovascular Pharmacology

JF - Journal of Cardiovascular Pharmacology

SN - 1533-4023

IS - 4

ER -