title: New molecular mechanisms for cardiovascular disease: contribution of endothelium-derived hyperpolarizing factor in the regulation of vasoconstriction in peripheral resistance arteries.
abstract: Endothelium regulates vascular tone via release of endothelium-derived relaxing factors (EDRF) including nitric oxide (NO), prostaglandin I₂ (PGI₂), and endothelium-derived hyperpolarizing factor (EDHF). The mesenteric vascular bed produces vascular resistance to develop blood pressure and regulate tissue blood flow that plays an important role in maintenance of systemic blood pressure. There is now strong evidence that in these small resistance arteries, EDHF plays a major role in the response to vasoactive substances and regulation of vascular tone. Pharmacological analysis to investigate the role of the vascular endothelium in the regulation of α₁-adrenoceptor agonist (methoxamine)-induced vasoconstriction in rat mesenteric vascular beds showed that vasoconstriction induced by continuous perfusion of methoxamine (7 µM), but not high KCl (60 mM), time-dependently decreased to 20% of the initial constriction. The time-dependent reduction of methoxamine-induced vasoconstriction was inhibited by endothelium removal, inhibitor of EDHF (30 mM KCl, K+-channel blockers), and gap-junction inhibitor, but not NO synthase inhibitor and cyclooxygenase inhibitor and ageing. These results suggest that vascular endothelium counteracts to normalize excess vasoconstriction of the mesenteric resistance arteries by releasing EDHF, which is associated with activation of multiple K+-channels and gap junction involvement and markedly decreases with ageing.
authors.affiliation: Department of Clinical Pharmaceutical Science, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Japan.
authors.forename: Xin
authors.initials: X
authors.lastname: Jin
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Satoh-Otonashi
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Zamami
authors.forename: Shingo
authors.initials: S
authors.lastname: Takatori
authors.forename: Narumi
authors.initials: N
authors.lastname: Hashikawa-Hobara
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Kitamura
authors.forename: Hiromu
authors.initials: H
authors.lastname: Kawasaki
mesh_terms: D000818:Animals; D001685:Biological Factors / Q000378:metabolism*; D002318:Cardiovascular Diseases / Q000378:metabolism* / Q000503:physiopathology*; D004730:Endothelium, Vascular / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D008638:Mesenteric Arteries / Q000378:metabolism* / Q000503:physiopathology; D014655:Vascular Resistance / Q000502:physiology; D014661:Vasoconstriction / Q000502:physiology
chemical_list: D001685:Biological Factors; C067410:endothelium-dependent hyperpolarization factor