[Pathological action of endothelin-1 on the heart: coronary spasm and arrhythmia]

Endothelin-1 (ET-1), the member of a newly discovered family of vasoactive peptides is the most aggressive endogenous vasoconstrictor agent known to science. This paper summarizes the recent work of a Hungarian research group related to the regulatory role of ET-1 in the mammalian heart. The results highlighted the unique pathophysiological and clinical features of the ET-1 action in the coronary vascular bed suggesting the potential role of the peptide in precipitating coronary spasm as well as its outstanding capacity for inducing cardiac arrhythmias. Contrary to the classical tenets of homeostasis, such effects do not reduce but increase variability and inhomogeneity (both in myocardial blood flow distribution and generation of electrical impulses), indicating the involvement of new types of regulatory principles in the cardiovascular system.