Characterization of β-Adrenoceptors in Pig Basilar Artery from Functional and Radioligand Binding Studies

The Japanese Journal of Pharmacology

Ken Ito¹  Akira Nishio¹  Atsushi Miyamoto¹ 

[1] Department of Veterinary Pharmacology, Faculty of Agriculture, Kagoshima University,

关键词: Basilar artery (pig);    Relaxation;    β1-Adrenoceptor;    Norepinephrine;    [3H]-Dihydroalprenolol;   

DOI  :  10.1254/jjp.61.93

学科分类：药理学

来源: Nihon Yakuri Gakkai Henshuubu / Japanese Pharmacological Society

【 摘 要 】

References(16)Cited-By(9)β-Adrenoceptors in pig basilar arteries were investigated by measuring the relaxation responses to norepinephrine and by a radioligand binding assay with [3H]-dihydroalprenolol (DHA). Norepinephrine induced concentration-dependent relaxations. The relaxation responses were independent of the presence of endothelial cells, and they were competitively antagonized by (±)-propranolol, atenolol, butoxamine and ICI 118, 551. Specific [3H]-DHA binding to β-adrenoceptors was saturable, reversible and high affinity (Kd=1.4 nM), with a Bmax of 48.7 fmol/mg protein. Computer analysis of inhibition of [3H]DHA binding by atenolol, butoxamine and ICI 118, 551 gave a β1:β2-adrenoceptor ratio of approximately 65:35. The pA2 values of these antagonists were significantly correlated with the Ki values for β1-adrenoceptor determined by the radioligand binding assay. The present findings indicate that the relaxation responses to norepinephrine are predominantly mediated through the stimulation of β1-adrenoceptors on vascular smooth muscle cells in a pig basilar artery.

【 授权许可】

Unknown