Endothelium enhances tachyphylaxis to angiotensins II and III in rat aorta.
Development of tachyphylaxis to angiotensin-induced contraction was compared in rings of rat aorta with and without functional endothelium. Rat aorta with functional endothelium rapidly developed marked tachyphylaxis to contraction induced by angiotensin II or angiotensin III. Destruction of endothelium significantly depressed, but did not prevent, development of tachyphylaxis to contractile responses induced by repeated exposure to angiotensin II or angiotensin III. The findings suggest that two mechanisms are involved in the development of tachyphylaxis to angiotensin in rat aorta, an endothelium-dependent mechanism and an endothelium-independent mechanism.
Gruetter
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Department of Pharmacology, Marshall University School of Medicine, Huntington, WV 25704.
Ryan
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Schoepp
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D000804:Angiotensin II / Q000031:analogs & derivatives* / Q000494:pharmacology*; D000805:Angiotensin III / Q000494:pharmacology*; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects; D004730:Endothelium, Vascular / Q000502:physiology*; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D013618:Tachyphylaxis
D000804:Angiotensin II; D000805:Angiotensin III