Heterogeneity of endothelin ETA receptor-mediated contractions in the rabbit saphenous vein.
The involvement of endothelin ETA receptors in endothelin-1-induced contractions of the rabbit saphenous vein was studied. After desensitization of endothelin ETB receptors by pretreatment with sarafotoxin S6c, endothelin-1 and sarafotoxin S6b and a high concentration of endothelin-3 caused dose-dependent contractions. However, endothelin-1-induced contractions were much less sensitive to an endothelin ETA receptor antagonist, BQ-123 (cyclo (-D-Asp-L-Pro-D-Val-L-Leu-D-Trp-)), than sarafotoxin S6b-induced responses. The pA2 values of BQ-123 for endothelin-1- and sarafotoxin S6b-induced contractions were 5.69 and 7.65, respectively. These results suggest pharmacological heterogeneity of endothelin ETA receptors in the rabbit saphenous vein.
Nishiyama
M
M
Division of Cardiovascular Biology, Chiba University School of Medicine, Japan.
Shan
L H
LH
Moroi
K
K
Masaki
T
T
Kimura
S
S
D000818:Animals; D016232:Endothelins / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D010456:Peptides, Cyclic / Q000494:pharmacology; D011817:Rabbits; D044022:Receptor, Endothelin A; D017466:Receptors, Endothelin / Q000502:physiology*; D012501:Saphenous Vein / Q000502:physiology*; D014661:Vasoconstriction / Q000187:drug effects*; D014757:Viper Venoms / Q000494:pharmacology
D016232:Endothelins; D010456:Peptides, Cyclic; D044022:Receptor, Endothelin A; D017466:Receptors, Endothelin; D014757:Viper Venoms; C057354:sarafotoxins s6; C072247:cyclo(Trp-Asp-Pro-Val-Leu)