title: Differential constrictor responses of cephalic and caudal vasculature to α-adrenoceptor agonist after hind limb unloading.
abstract: We examined the effects of hind limb unloading (HLU, 14 days) on constriction of carotid and iliac arterial beds in vivo in thiobutabarbital-anaesthetized rats and isolated carotid and iliac arteries in vitro. Both control and HLU rats had similar arterial pressure and carotid and iliac arterial flows. The HLU rats had increased carotid arterial but reduced iliac arterial constriction in response to methoxamine (α1-adrenoceptor agonist) in vivo. In contrast, constriction in response to methoxamine was reduced in the isolated carotid and unchanged in the iliac artery of HLU rats relative to control rats. Thus, HLU is associated with increased constriction of carotid arterial bed but reduced constriction of the isolated carotid artery, and reduced constriction of iliac arterial bed but unchanged constriction of the isolated iliac artery. These results show differential influence of HLU on constriction of cephalic and caudal arterial beds, and differential effect on constrictions of arterial beds relative to conduit arteries.
authors.affiliation: Department of Anesthesiology, Pharmacology, and Therapeutics, Faculty of Medicine, The University of British Columbia, 2176 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada.
authors.forename: Simon R
authors.initials: SR
authors.lastname: Hutchings
authors.forename: Jong Moo
authors.initials: JM
authors.lastname: Kim
authors.forename: Dongzhe
authors.initials: D
authors.lastname: Song
authors.forename: Catherine C Y
authors.initials: CC
authors.lastname: Pang
mesh_terms: D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002339:Carotid Arteries / Q000187:drug effects* / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D019417:Hindlimb Suspension; D007083:Iliac Artery / Q000187:drug effects* / Q000502:physiology; D008150:Lower Body Negative Pressure; D008297:Male; D008729:Methoxamine / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D014661:Vasoconstriction / Q000187:drug effects*
chemical_list: D000316:Adrenergic alpha-Agonists; D008729:Methoxamine