title: Resting load and modulation of the myofilament Ca2+ sensitivity in rabbit cerebral arteries.
abstract: The effect of preload on myofilament Ca2+ sensitivity was examined using alpha-toxin permeabilization and fura-2 fluorometry in rabbit cerebral arteries. The [Ca2+]i-force curves shifted leftward at a high preload, with a decrease in median effective concentration of Ca2+ in the permeabilized artery. In the fura-2-loaded artery, the preload modulated the force without affecting [Ca2+]i levels during K+ depolarization, and a high preload moved the [Ca2+]i-force curve upward and to the left. It is thus concluded that the preload regulates the Ca2+ sensitivity of the myofilament and, therefore, may play a role in the regulation of cerebral arterial tonus and blood flow.
authors.affiliation: Division of Molecular Cardiology, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
authors.forename: X
authors.initials: X
authors.lastname: Chen
authors.forename: Y
authors.initials: Y
authors.lastname: Miyagi
authors.forename: J
authors.initials: J
authors.lastname: Nishimura
authors.forename: S
authors.initials: S
authors.lastname: Kobayashi
authors.forename: M
authors.initials: M
authors.lastname: Fukui
authors.forename: H
authors.initials: H
authors.lastname: Kanaide
mesh_terms: D008841:Actin Cytoskeleton / Q000187:drug effects*; D000818:Animals; D001488:Basilar Artery / Q000187:drug effects / Q000648:ultrastructure; D002118:Calcium / Q000494:pharmacology*; D002536:Cerebral Arteries / Q000502:physiology* / Q000648:ultrastructure; D002560:Cerebrovascular Circulation; D004351:Drug Resistance; D004423:Ear / Q000098:blood supply; D005456:Fluorescent Dyes; D005470:Fluorometry; D016257:Fura-2; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D011817:Rabbits; D013314:Stress, Mechanical; D014661:Vasoconstriction / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000494:pharmacology*; D014666:Vasomotor System / Q000187:drug effects*
chemical_list: D005456:Fluorescent Dyes; D014662:Vasoconstrictor Agents; D002118:Calcium; D016257:Fura-2