Angiotensin II contractions in coronary artery

Pig coronary artery rings denuded of endothelium contract to the vasoactive hormone angiotensin II (Ang II). The nature of Ang II receptors and their Ca2+-pool utilization were examined for contraction of the artery rings and for increase in ultracellular [Ca2+] ([Ca2+]i) in smooth muscle cells cultured from them. Ang II contracted the arteries (EC50=7±4 nM) but with a lower maximal force (1.4±0.25 N/g tissue) than the contraction with 60 mM K+ …