Identification and characterization of the alpha 2D-adrenoceptor subtype in single cells prepared from guinea pig tracheal smooth muscles.
Single cells were prepared from guinea pig tracheal smooth muscle and used in binding studies of [3H]p-aminoclonidine. Specific binding of [3H]p-aminoclonidine was saturable to a single class of receptors, with an equilibrium dissociation constant (KD) of 1.62 +/- 0.17 nM and a density (Bmax) of 6.20 +/- 0.78 x 10(4) sites/cell. Competition studies were carried out with several adrenergic antagonists. The rank order of potency was idazoxan = phentolamine > yohimbine > prazosin = corynanthine. These results suggest that the alpha 2-adrenoceptor in guinea pig tracheal smooth muscle represents a single pharmacological subtype, which is designated as alpha 2D.
Department of Chemical Pharmacology, Toho University School of Pharmaceutical Sciences, Chiba, Japan.
M
M
Satoh
I
I
Takayanagi
D000316:Adrenergic alpha-Agonists / Q000378:metabolism; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D001667:Binding, Competitive / Q000187:drug effects; D003000:Clonidine / Q000031:analogs & derivatives / Q000378:metabolism; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007700:Kinetics; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism*; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism*; D014132:Trachea / Q000166:cytology / Q000378:metabolism
D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D011942:Receptors, Adrenergic, alpha; C016986:apraclonidine; D003000:Clonidine