Human vascular responses to endothelin-1: observations in vivo and in vitro.
These studies have investigated the effect of endothelin-1 (ET-1) on human resistance vasculature in vivo and in vitro. ET-1 was infused via the brachial artery and forearm blood flow (FBF) measured by venous occlusion plethysmography. Isolated resistance vessels were studied in a myograph. ET-1 (10 pmol-10 nmol/min, i.a.) reduced forearm blood flow. Endothelin-1-induced forearm vasoconstriction was slow to recover following washout. ET-1 (10 pM-10 nM) contracted isolated human subcutaneous and omental resistance vessels. Contractile responses to ET-1 were sustained and washout recovery was slow. Responses to ET-1 displayed marked tachyphylaxis. Calcium channel blockers and removal of extracellular calcium failed to completely abolish responses to ET-1 in vitro.
Hughes
A D
AD
Department of Clinical Pharmacology, St. Mary's Hospital Medical School, London, England.
Thom
S A
SA
Woodall
N
N
Schachter
M
M
Hair
W M
WM
Martin
G N
GN
Sever
P S
PS
D000328:Adult; D002118:Calcium / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D016232:Endothelins; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D010455:Peptides / Q000494:pharmacology*; D012039:Regional Blood Flow / Q000187:drug effects; D014655:Vascular Resistance / Q000187:drug effects*; D014700:Verapamil / Q000494:pharmacology
D016232:Endothelins; D010455:Peptides; D014700:Verapamil; D002118:Calcium