Intracellular administration of angiotensin II reduced the peak inward calcium current by 35% in adult rat ventricular myocytes (P<0.05) but increased it by 36% in hamster myocytes.
Intracellular angiotensin II regulates inward calcium current and myocardial contractility in a species-dependent manner, independent of surface AT1 receptors.
p-value: p=<0.05
-The influence of intracellular administration of angiotensin II (Ang II) on the inward calcium current (ICa) was investigated in single myocytes isolated from adult rat ventricle. Comparative studies were also made in ventricular cells of Golden hamsters. The ICa was measured in single cells using the whole-cell voltage clamp configuration. The results indicated that Ang II (10(-8) mmol/L) dialyzed into the rat myocytes reduced the peak ICa by 35+/-5.5% (n=20; P0.05). The effect of the peptide was not altered by the intracellular administration of losartan (10(-6) mmol/L), by Sar1Val5Ala8 Ang II (10(-6) mmol/L), or by the inhibitor of protein kinase A. The inhibition of protein kinase C, however, prevented the effect of Ang II ICa in the hamster myocytes. The results particularly suggest that the activation of the cardiac renin-angiotensin system regulates ICa and myocardial contractility, an effect that varies with the species.
Walmor C. De Mello (Tue,) reported a other. Intracellular angiotensin II was evaluated on Peak inward calcium current (ICa) (p=<0.05). Intracellular administration of angiotensin II reduced the peak inward calcium current by 35% in adult rat ventricular myocytes (P<0.05) but increased it by 36% in hamster myocytes.