title: Interaction of synthetic sarafotoxin with rat vascular endothelin receptors.
abstract: The effects of synthetic analogs of sarafotoxin (STX) S6b, a snake venom peptide with a high sequence homology to the endothelium-derived vasoconstrictor endothelin (ET), on ET receptor binding activity and cytosolic free Ca2+ concentration [( Ca2+]i) were studied in cultured rat vascular smooth muscle cells. Binding studies revealed that [Cys1-15, Cys3-11] STX competed with 125I-ET for the binding to its vascular receptors with lower affinity than that of ET, but was far more effective than [Cys1-11, Cys3-15]STX in inhibiting the binding. [Cys1-15, Cys3-11]STX had a less potent effect on increasing [Ca2+]i than ET, whereas [Cys1-11, Cys3-15]STX was inactive. These data suggest that there may exist heterogenous subpopulations of the vascular ET/STX receptors, and that the proper double cyclic structure of STX is essential for interacting with its putative receptors to induce the [Ca2+]i response.
authors.affiliation: Department of Medicine, Tokyo Medical and Dental University, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Hirata
authors.forename: H
authors.initials: H
authors.lastname: Yoshimi
authors.forename: F
authors.initials: F
authors.lastname: Marumo
authors.forename: T X
authors.initials: TX
authors.lastname: Watanabe
authors.forename: S
authors.initials: S
authors.lastname: Kumagaye
authors.forename: K
authors.initials: K
authors.lastname: Nakajima
authors.forename: T
authors.initials: T
authors.lastname: Kimura
authors.forename: S
authors.initials: S
authors.lastname: Sakakibara
mesh_terms: D000818:Animals; D001667:Binding, Competitive; D002478:Cells, Cultured; D004220:Disulfides; D004730:Endothelium, Vascular / Q000378:metabolism*; D007700:Kinetics; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D011956:Receptors, Cell Surface / Q000187:drug effects / Q000378:metabolism*; D017466:Receptors, Endothelin; D014662:Vasoconstrictor Agents / Q000378:metabolism / Q000494:pharmacology*; D014757:Viper Venoms / Q000138:chemical synthesis / Q000494:pharmacology*
chemical_list: D004220:Disulfides; D011956:Receptors, Cell Surface; D017466:Receptors, Endothelin; D014662:Vasoconstrictor Agents; D014757:Viper Venoms; C057354:sarafotoxins s6