title: Antihypertensive mechanism of the dipeptide Val-Tyr in rat aorta.
abstract: Antihypertensive peptides received much interest over the last decade. These peptides are known to be angiotensin converting enzyme (ACE) inhibitors in vitro, but the actual antihypertensive mechanisms in vivo are still unclear. In this research, we used rat aortic rings in organ bath experiments to investigate five potential vascular antihypertensive mechanisms of the dipeptide Val-Tyr. Only one significant effect was observed, namely preincubation of the aorta with Val-Tyr led to a significant shift of the concentration-response curve evoked by angiotensin I (Ang I). Val-Tyr had no effect on the angiotensin II receptor or the alpha-adrenergic receptor. Furthermore, it did not interact with voltage-operated Ca2+ channels, or with nitric oxide production/availability. In conclusion, our results show that Val-Tyr specifically inhibits Ang I-evoked contraction through ACE inhibition and that four other main mechanisms of vascular tone regulation are not affected.
authors.affiliation: Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium. Lieselot.Vercruysse@UGent.be
authors.forename: Lieselot
authors.initials: L
authors.lastname: Vercruysse
authors.forename: Nicole
authors.initials: N
authors.lastname: Morel
authors.forename: John
authors.initials: J
authors.lastname: Van Camp
authors.forename: Justyna
authors.initials: J
authors.lastname: Szust
authors.forename: Guy
authors.initials: G
authors.lastname: Smagghe
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000803:Angiotensin I / Q000494:pharmacology; D000804:Angiotensin II / Q000494:pharmacology; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology; D000818:Animals; D000959:Antihypertensive Agents / Q000737:chemistry / Q000494:pharmacology*; D001011:Aorta / Q000187:drug effects* / Q000502:physiology; D004151:Dipeptides / Q000737:chemistry / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D016166:Free Radical Scavengers / Q000737:chemistry / Q000494:pharmacology; D066298:In Vitro Techniques; D017706:Lisinopril / Q000737:chemistry / Q000494:pharmacology; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology; D009842:Oligopeptides / Q000737:chemistry / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D014661:Vasoconstriction / Q000187:drug effects*
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents; D004151:Dipeptides; D016166:Free Radical Scavengers; D009842:Oligopeptides; C414029:valyltyrosine; D000804:Angiotensin II; C010980:hippuryl-histidyl-leucine; D011189:Potassium Chloride; D000803:Angiotensin I; D017706:Lisinopril; D000109:Acetylcholine; D009638:Norepinephrine