title: Effects of K+ channel openers on the vascular actions of human gamma globulin.
abstract: The aim of this study was to determine if the stimulatory action of human gamma globulin on the spontaneous activity of the rat mesenteric portal vein is due to decreased K+ conductance. Glibenclamide potentiated the action of human gamma-globulin on the portal vein by 45% and on its own had a concentration- and time-dependent biphasic (increase followed by a decrease) effect on the spontaneous activity of the portal vein. Diazoxide and pinacidil both inhibited the action of human gamma-globulin on the rat mesenteric portal vein. Levcromakalim (BRL 38227) potentiated the stimulatory action of human gamma-globulin on the integrated force of the spontaneous contractions of the rat mesenteric portal vein by 40% and 49% at concentrations of 0.5 and 5 microM, respectively. These studies suggest that human gamma-globulin can act by directly modulating a K+ channel.
authors.affiliation: Department of Pharmacology and Therapeutics, Faculty of Medicine, University of British Columbia, Vancouver, Canada.
authors.forename: Z
authors.initials: Z
authors.lastname: Abrahams
authors.forename: M C
authors.initials: MC
authors.lastname: Sutter
mesh_terms: D000818:Animals; D003981:Diazoxide / Q000494:pharmacology; D005905:Glyburide / Q000494:pharmacology; D006146:Guanidines / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D009638:Norepinephrine / Q000494:pharmacology; D020110:Pinacidil; D011169:Portal Vein / Q000187:drug effects; D015221:Potassium Channels / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D014665:Vasodilator Agents / Q000494:pharmacology; D005719:gamma-Globulins / Q000037:antagonists & inhibitors / Q000494:pharmacology*
chemical_list: D006146:Guanidines; D015221:Potassium Channels; D014665:Vasodilator Agents; D005719:gamma-Globulins; D020110:Pinacidil; D003981:Diazoxide; D005905:Glyburide; D009638:Norepinephrine