Microvascular responses to endothelin in deoxycorticosterone acetate-salt hypertensive rats.
The objective of the present study was to determine if endothelin-1 played a role in the elevated peripheral resistance in deoxycorticosterone-acetate (DOCA)-salt hypertension. Radioimmunoassay showed that the concentration of endothelin-1 was higher in thoracic aorta of the DOCA-salt group than that of the control normotensive (CN) group. Responses of arterioles in the rat cremaster to endothelin-1 were also observed using in vivo closed circuit television microscopy. Microvascular sensitivity to endothelin-1 was decreased in the DOCA-salt group. In the presence of an endothelin type A (ET-A) receptor antagonist, low concentrations of endothelin-1 induced a significant vasoconstriction in the DOCA-salt group. In the presence of endothelin type B (ET-B) receptor antagonist, microvascular responses to endothelin-1 were attenuated in the DOCA-salt group. These results indicated that the increased tissue level of endothelin-1 may decrease the ET-A receptor-mediated vascular response to endothelin-1. However, the ET-B receptor-mediated vasoconstriction is potentiated during DOCA-salt hypertension.
Zhao
H
H
Department of Physiology and Biophysics, University of Louisville, School of Medicine, Kentucky 40292, USA.
Joshua
I G
IG
Porter
J P
JP
D000818:Animals; D001013:Aorta, Thoracic; D003900:Desoxycorticosterone; D004305:Dose-Response Relationship, Drug; D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1 / Q000097:blood / Q000494:pharmacology*; D006973:Hypertension / Q000139:chemically induced* / Q000503:physiopathology*; D008297:Male; D008833:Microcirculation / Q000187:drug effects; D018482:Muscle, Skeletal / Q000098:blood supply; D009842:Oligopeptides / Q000494:pharmacology; D010456:Peptides, Cyclic / Q000494:pharmacology; D010880:Piperidines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D044022:Receptor, Endothelin A; D044023:Receptor, Endothelin B; D012965:Sodium Chloride
D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1; D009842:Oligopeptides; D010456:Peptides, Cyclic; D010880:Piperidines; D044022:Receptor, Endothelin A; D044023:Receptor, Endothelin B; D003900:Desoxycorticosterone; C086539:BQ 788; D012965:Sodium Chloride; C072247:cyclo(Trp-Asp-Pro-Val-Leu)