Functional significance of angiotensin receptors in human myocardium. Significant differences between atrial and ventricular myocardium.
We studied the effects of angiotensin (Ang) I and II in a variety of isolated human cardiac tissues contracting under physiological conditions (37 degrees C, 60 beats.min-1). Ang I and II consistently increased the peak developed force of human atrial muscles by 30-40%, an effect that was completely blocked by 10(-6) M saralasine, but not by the combination of prazosin and propranolol. However, neither Ang I or II had significant inotropic effects in right and left ventricular human preparations. We were also able to demonstrate that the positive inotropic effect of Ang II in human right atrial tissue is mediated by the AT1 receptor subtype but not the AT2 receptor subtype.
Holubarsch
C
C
Department of Cardiology and Angiology, University of Freiburg, Germany.
Schmidt-Schweda
S
S
Knorr
A
A
Duis
J
J
Pieske
B
B
Ruf
T
T
Fasol
R
R
Hasenfuss
G
G
Just
H
H
D000803:Angiotensin I / Q000502:physiology; D000804:Angiotensin II / Q000502:physiology; D016275:Atrial Function; D046508:Culture Techniques; D004305:Dose-Response Relationship, Drug; D006325:Heart Atria / Q000187:drug effects; D006352:Heart Ventricles / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D009200:Myocardial Contraction / Q000187:drug effects / Q000502:physiology*; D011224:Prazosin / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D011945:Receptors, Angiotensin / Q000187:drug effects / Q000502:physiology*; D012504:Saralasin / Q000494:pharmacology; D016276:Ventricular Function
D011945:Receptors, Angiotensin; D000804:Angiotensin II; D000803:Angiotensin I; D011433:Propranolol; D012504:Saralasin; D011224:Prazosin