The development of potent peptide agonists and antagonists for the endothelin receptors

The endothelins (ETs), sarafotoxins (SRTXs), vasoactive intestinal contractor (VIC), and bibrotoxin are a family of potent vasoconstrictor peptides. All peptides in this family possess 21 amino acids arranged in a unique bicyclic motif formed between cystine bridges in the 1-15 and 3-11 positions. Since the discovery of endothelin-1 (ET-1) in 1988, significant effort has been focused on the understanding of its structure-activity relationships. The identification of endothelin receptor subtypes has led to the discovery/design of potent peptide agonists and antagonists, along with nonpeptide antagonists of endothelin with varying levels of potency and receptor subtype selectivity. In keeping with the theme of this journal, this review will focus only on the development of peptidic-based agonists and antagonists of endothelin in addition to their applications in understanding the physiological and/or pathophysiological role of endothelin and its isopeptides.