Differences in alpha 1-adrenoceptor mechanisms for phenylephrine and tizanidine in rabbit thoracic aorta and common iliac artery.
Based on affinity for WB4101 and susceptibility to chloroethylclonidine, we evaluated the subtype of alpha 1-adrenoceptors activated by phenylephrine (a full agonist) and tizanidine (a partial agonist). The rabbit thoracic aorta and common iliac artery contain both alpha 1A- and alpha 1B-adrenoceptors, but the alpha 1B-subtype may be more predominantly in the common iliac artery than in the thoracic aorta. In rabbit thoracic aorta and common iliac artery, phenylephrine induced contraction through both alpha 1A- and alpha 1B-subtypes and tizanidine through only the alpha 1A-subtype. The subtype activated by phenylephrine may be partly different from that activated by tizanidine in the preparations used herein.
Takayanagi
I
I
Department of Chemical Pharmacology, Toho University School of Pharmaceutical Sciences, Chiba, Japan.
Harada
M
M
Koike
K
K
Satoh
M
M
D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects / Q000378:metabolism; D003000:Clonidine / Q000031:analogs & derivatives / Q000494:pharmacology; D004146:Dioxanes / Q000494:pharmacology; D007083:Iliac Artery / Q000187:drug effects / Q000378:metabolism; D066298:In Vitro Techniques; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D010656:Phenylephrine / Q000494:pharmacology; D011817:Rabbits; D011942:Receptors, Adrenergic, alpha / Q000145:classification* / Q000187:drug effects / Q000378:metabolism; D014018:Tissue Distribution; D014661:Vasoconstriction / Q000187:drug effects
D004146:Dioxanes; D011942:Receptors, Adrenergic, alpha; D010656:Phenylephrine; C051731:chlorethylclonidine; C023754:tizanidine; C010654:(2-(2',6'-dimethoxy)phenoxyethylamino)methylbenzo-1,4-dioxane; D003000:Clonidine