title: alpha2-Adrenoceptor activation increases calcium channel currents in single vascular smooth muscle cells isolated from human omental resistance arteries.
abstract: Single cells were freshly isolated from human omental resistance arteries using an enzymatic dispersion technique. Calcium channel currents (IBa) were recorded using whole cell voltage clamp techniques with Ba2+ as the charge carrier. BHT 933, a selective alpha2-adrenoceptor agonist, increased IBa. The effect of BHT 933 was reversible following washout. The action of BHT 933 was blocked by yohimbine. Pretreatment of tissues with pertussis toxin for 18 h or inclusion of GDP-beta-S in the intracellular patch pipette solution also prevented the BHT 933-induced rise in IBa, but had no effect on IBa in the absence of BHT 933. Activation of alpha2-adrenoceptors in human vascular smooth muscle cells increases IBa by a mechanism involving a pertussis toxin-sensitive G protein.
authors.affiliation: Department of Clinical Pharmacology, Imperial College of Science Technology and Medicine, London, UK.
authors.forename: A D
authors.initials: AD
authors.lastname: Hughes
authors.forename: N A
authors.initials: NA
authors.lastname: Parkinson
authors.forename: S
authors.initials: S
authors.lastname: Wijetunge
mesh_terms: D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D001158:Arteries / Q000502:physiology; D001381:Azepines / Q000494:pharmacology; D001464:Barium / Q000378:metabolism; D015220:Calcium Channels / Q000502:physiology*; D002469:Cell Separation; D004553:Electric Conductivity; D006153:Guanosine Diphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D006801:Humans; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D009852:Omentum / Q000098:blood supply*; D037342:Pertussis Toxin; D011942:Receptors, Adrenergic, alpha / Q000502:physiology*; D013873:Thionucleotides / Q000494:pharmacology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology; D015016:Yohimbine / Q000494:pharmacology
chemical_list: D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D001381:Azepines; D015220:Calcium Channels; D011942:Receptors, Adrenergic, alpha; D013873:Thionucleotides; D010566:Virulence Factors, Bordetella; D006153:Guanosine Diphosphate; D001464:Barium; D015016:Yohimbine; C023427:guanosine 5'-O-(2-thiodiphosphate); C015603:azepexole; D037342:Pertussis Toxin