Sarafotoxin S6c: an agonist which distinguishes between endothelin receptor subtypes

Biochem Biophys Res Commun. 1991 Mar 15;175(2):556-61. doi: 10.1016/0006-291x(91)91601-8.


In contrast to endothelin-1 (ET-1) and several of its analogues, sarafotoxin S6c (S6c) was a much more potent inhibitor of [125I]-ET-1 binding in rat hippocampus and cerebellum (Ki approximately 20 pM) than in rat atria and aorta (Ki approximately 4500 nM), suggesting the existence of ET-1 receptor subtypes (aorta/atria, ETA; hippocampus/cerebellum, ETB). S6c was a potent activator of PI turnover in hippocampus (EC50 approximately 10 nM) but not atria (EC50 greater than 1 microM), unlike ET-1 which was active in both tissues. S6c, therefore, is a highly selective ETB agonist. Furthermore, S6c was a potent pressor agent in the pithed rat (ED25 mm Hg approximately 0.1 nmoles/kg, i.v.), suggesting that the ETB receptor subtype may be important in cardiovascular function.

MeSH terms

  • Animals
  • Aorta / metabolism
  • Binding Sites
  • Binding, Competitive
  • Blood Pressure / drug effects
  • Cerebellum / metabolism
  • Endothelins / metabolism*
  • Heart Atria / metabolism
  • Hippocampus / metabolism
  • Kidney Medulla / metabolism
  • Phosphatidylinositols / metabolism
  • Rats
  • Receptors, Cell Surface / drug effects*
  • Receptors, Cell Surface / metabolism
  • Receptors, Endothelin
  • Viper Venoms / metabolism
  • Viper Venoms / pharmacology*


  • Endothelins
  • Phosphatidylinositols
  • Receptors, Cell Surface
  • Receptors, Endothelin
  • Viper Venoms
  • sarafotoxins s6