Positive chronotropic effects of endothelin, a novel endothelium-derived vasoconstrictor peptide

Abstract

Endothelin (ET) is a novel 21-amino-acid peptide isolated from the culture supernatant of porcine aortic endothelial cells, which has a potent vasoconstricting effect. It has been suggested that ET increases Ca²⁺ influx via a voltage-dependent Ca²⁺ channel. The purpose of the present study is to investigate the mode of actions of ET on the cardiac automaticity. ET increased the sinoatrial nodal rate in a dose-dependent manner on the isolated right atria of guinea pigs. The positive chronotropic effect of ET was very potent and the ED₅₀ value was 0.4 nM. These results suggest that ET is one of the most potent cardio-acceleratory substances.