Nakagoshi A, Koike K, Takayanagi I
Department of Chemical Pharmacology, Toho University School of Pharmaceutical Sciences, Chiba, Japan.
Can J Physiol Pharmacol. 1987 Nov;65(11):2163-7. doi: 10.1139/y87-341.
The effect of pretreatment with egg albumin was examined on the beta-adrenoceptors in guinea pig isolated trachea. Befunolol and carteolol acted as partial agonists and their pA2 values were significantly larger than their corresponding pD2 values in tracheae from both untreated guinea pigs and those treated with egg albumin, suggesting that the beta-adrenoceptors contain two different affinity sites. The Scatchard plot of specific [3H]befunolol binding showed two affinity sites of the receptor (high and low affinity sites) in tracheae from both untreated animals and those treated with egg albumin. The pKD values of befunolol for both low and high affinity sites were in agreement with their respective pD2 and pA2 values. The intrinsic activities of befunolol and carteolol and the pD2 values of the test drugs were decreased by the treatment with egg albumin. The treatment with egg albumin also decreased the total amount of the two affinity sites of the receptor without any change in affinity. The present results support the partial blockade of beta-adrenoceptors in asthma proposed by Szentivanyi.
研究了用蛋清蛋白预处理对豚鼠离体气管中β-肾上腺素能受体的影响。倍他洛尔和卡替洛尔作为部分激动剂，在未处理的豚鼠以及用蛋清蛋白处理的豚鼠的气管中，它们的pA2值显著大于相应的pD2值，这表明β-肾上腺素能受体含有两个不同的亲和力位点。特异性[3H]倍他洛尔结合的Scatchard图显示，在未处理动物和用蛋清蛋白处理的动物的气管中，受体有两个亲和力位点（高亲和力位点和低亲和力位点）。倍他洛尔对低亲和力位点和高亲和力位点的pKD值与其各自的pD2和pA2值一致。用蛋清蛋白处理后，倍他洛尔和卡替洛尔的内在活性以及受试药物的pD2值降低。用蛋清蛋白处理还降低了受体两个亲和力位点的总量，而亲和力没有任何变化。目前的结果支持了Szentivanyi提出的哮喘中β-肾上腺素能受体部分阻断的观点。
