title: Vascular relaxation by ifenprodil in the isolated perfused rat mesenteric artery.
abstract: The possible mechanism of vascular relaxation by ifenprodil has been examined in the isolated perfused rat mesenteric artery preparation. Ifenprodil (5.0 X 10(-9)-5.0 X 10(-8) M) noncompetitively blocked noradrenaline- and cirazoline-induced vasoconstrictor responses. This concentration range did not affect responses to 5-hydroxytryptamine and potassium chloride. However, in concentrations above 10(-6) M, ifenprodil caused (a) reversal of constrictor responses to excess potassium given either by bolus injections (3.4 X 10(-2)-5.4 X 10(-1) M) or by continuous perfusion (55 mM) and (b) inhibition of Ca2+-induced constrictor effects in arteries perfused with Ca2+-free depolarizing Krebs solution. It is concluded that ifenprodil blocks Ca2+ mobilization through both the ion channels coupled to alpha-adrenoceptors and the potential-sensitive channels.
mesh_terms: D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology*; D000818:Animals; D007093:Imidazoles / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects* / Q000502:physiology; D009126:Muscle Relaxation / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D009638:Norepinephrine / Q000494:pharmacology; D010646:Phentolamine / Q000494:pharmacology; D010880:Piperidines / Q000494:pharmacology*; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D012701:Serotonin / Q000494:pharmacology; D014661:Vasoconstriction / Q000187:drug effects*; D014700:Verapamil / Q000494:pharmacology
chemical_list: D000317:Adrenergic alpha-Antagonists; D007093:Imidazoles; D010880:Piperidines; D012701:Serotonin; D011189:Potassium Chloride; D014700:Verapamil; C014282:cirazoline; C010739:ifenprodil; D009638:Norepinephrine; D010646:Phentolamine