Analysis of vasocontractile responses to endothelin-1 in rabbit retinal vessels using an ETA receptor antagonist and an ETB receptor agonist.
To study the role of endothelin receptor subtypes in rabbit retinal arteries, endothelin-1 (ET-1)-induced vasoconstriction was analyzed using the ETA receptor antagonist BQ-123 and the ETB receptor agonist BQ-3020. A cumulative injection of ET-1 (1 approximately 100 pmole) into the posterior vitreous body in anesthetized rabbits caused dose-dependent vasoconstriction in the retinal arteries, and ultimately caused complete obstruction. Fifteen minutes after BQ-123 (1 mumole) was injected into the posterior vitreous body, the dose-response curve of ET-1 was significantly shifted to the right. Intravitreal injection of BQ-3020 caused a significant retinal vasoconstriction only at the highest dose (1000 pmole). Therefore, in rabbit retinal arteries, ET-1-induced vasoconstriction appears to be mediated mainly through ETA receptors.
Takei
K
K
Department of Ophthalmology, University of Tsukuba, Ibaraki, Japan.
Sato
T
T
Nonoyama
T
T
Hommura
S
S
Miyauchi
T
T
Goto
K
K
D000818:Animals; D004305:Dose-Response Relationship, Drug; D065128:Endothelin Receptor Antagonists; D016232:Endothelins / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D005260:Female; D008297:Male; D010446:Peptide Fragments / Q000494:pharmacology; D010456:Peptides, Cyclic / Q000494:pharmacology; D011817:Rabbits; D044022:Receptor, Endothelin A; D044023:Receptor, Endothelin B; D017466:Receptors, Endothelin / Q000187:drug effects*; D012161:Retinal Artery / Q000187:drug effects* / Q000502:physiology; D014661:Vasoconstriction / Q000187:drug effects*
D065128:Endothelin Receptor Antagonists; D016232:Endothelins; D010446:Peptide Fragments; D010456:Peptides, Cyclic; D044022:Receptor, Endothelin A; D044023:Receptor, Endothelin B; D017466:Receptors, Endothelin; C075771:BQ 3020; C072247:cyclo(Trp-Asp-Pro-Val-Leu)