Microphysiometric analysis of human α1a‐adrenoceptor expressed in Chinese hamster ovary cells
Microphysiometric analysis of human α1a‐adrenoceptor expressed in Chinese hamster ovary cells
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DOI：
10.1038/sj.bjp.0702609
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发表时间：
1999-06
影响因子：
7.3
通讯作者：
T. Taniguchi;R. Inagaki;S. Murata;I. Akiba;I. Muramatsu
中科院分区：
文献类型：
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作者：
T. Taniguchi;R. Inagaki;S. Murata;I. Akiba;I. Muramatsu
人重组α1a-肾上腺素受体（AR）已在中国仓鼠卵巢细胞中稳定表达。分别表达30、370、940和2900 fmol AR mg− 1蛋白的4个稳定克隆aH 4、aH 5、aH 6和aH 7已被用于使用放射性配体结合和微生理测量法来表征该AR亚型，以测量细胞外酸化速率。NA的效价随着受体密度的增加而增加，克隆aH 4、aH 5、aH 6和aH 7的NA的pEC_（50）值分别为6.9、7.5、7.8和8.1。根据受体密度的效力增加表明存在NA的备用受体。甲氧胺、苯乙双胍、羟甲唑啉和可乐定也产生浓度依赖性反应，具有不同的内在活性。拮抗剂以浓度依赖性方式移动NA的浓度-反应曲线。Schild分析显示，该AR亚型对克隆aH 7中拮抗剂的亲和力特征具有典型的α1a-AR模式;对哌唑嗪和WB 4101具有高亲和力，对BMY 7378具有低亲和力（pA 2分别为9.5、9.8和7.3）。该图谱与克隆aH 4的情况相似。这些结果表明，（1）经典受体理论可以应用于微生理测量，（2）微生理测量是研究α1a-AR药理学特征的有用工具。British Journal of Pharmacology（1999）127，962-968; doi：10.1038/sj.bjp.0702609
The human recombinant α1a‐adrenoceptor (AR) has been stably expressed in Chinese hamster ovary cells. Four stable clones, aH4, aH5, aH6 and aH7, expressing 30, 370, 940 and 2900 fmol AR mg−1protein, respectively, have been employed to characterize this AR subtype using radioligand binding and microphysiometry to measure extracellular acidification rates.Noradrenaline (NA) gave concentration‐dependent responses in microphysiometry with increasing extracellular acidification rates. The potency of NA increased as the receptor density increased; pEC50values of NA for the clones aH4, aH5, aH6 and aH7 were 6.9, 7.5, 7.8 and 8.1, respectively. This increase of potency according to receptor density indicates the presence of spare receptor for NA. Methoxamine, phenylephrine, oxymetazoline and clonidine also gave concentration‐dependent responses with various intrinsic activities.Antagonists shifted concentration‐response curves for NA rightward in a concentration‐dependent manner. Schild analysis revealed that the affinity profile of this AR subtype to antagonists in the clone aH7 had a typical pattern for the α1a‐AR; high affinity for prazosin and WB 4101, and low affinity for BMY7378 (pA2=9.5, 9.8 and 7.3, respectively). This profile is similar in the case of the clone aH4. These affinities were in good agreement with those obtained in binding experiments.These results have demonstrated that (1) classical receptor theory can be applied in microphysiometry, and (2) microphysiometry is a useful tool to investigate the pharmacological characterization of α1a‐AR.British Journal of Pharmacology(1999)127, 962–968; doi:10.1038/sj.bjp.0702609