Baxter G T, Young M L, Miller D L, Owicki J C
Molecular Devices Corp., Menlo Park, CA 94025.
Life Sci. 1994;55(8):573-83. doi: 10.1016/0024-3205(94)00483-8.
The microphysiometer, an instrument that uses a semiconductor-based sensor to monitor cellular metabolic activity, has been shown to detect the activation of a variety of receptors in living cells, largely irrespective of the signal-transduction mechanism. Using the Cytosensor Microphysiometer, we have studied agonist concentration responses for the activation of CHO-K1 cell lines exogenously expressing rat m1 or m3 receptors. Three levels of receptor expression were investigated for each subtype. Carbachol is more potent for m3 than m1 receptors (0.5 to 1.0 log unit lower EC50); for both, potency correlates positively with receptor density. The results agree well with those obtained by measuring phosphoinositide hydrolysis and intracellular [CA++] in the same cells. We also determined that two subtype-selective antagonists, pirenzepine (for m1) and p-fluoro-hexahydrosila-difenidol (for m3) displayed appropriate differential ability to shift carbachol concentration-response curves in the microphysiometer. This study provides additional evidence that pharmacological results obtained by microphysiometry are consistent with those obtained by more conventional functional assays.
微生理仪是一种利用基于半导体的传感器来监测细胞代谢活性的仪器，已被证明能够检测活细胞中多种受体的激活情况，这在很大程度上与信号转导机制无关。我们使用细胞传感器微生理仪，研究了外源性表达大鼠m1或m3受体的CHO-K1细胞系激活时的激动剂浓度反应。对每个亚型研究了三种受体表达水平。卡巴胆碱对m3受体的作用强于m1受体（EC50低0.5至1.0对数单位）；对于两者，效力均与受体密度呈正相关。这些结果与通过测量同一细胞中的磷酸肌醇水解和细胞内[Ca++]所获得的结果非常吻合。我们还确定，两种亚型选择性拮抗剂，哌仑西平（针对m1）和对氟六氢硅二苯醚（针对m3）在微生理仪中显示出适当的差异能力，可使卡巴胆碱浓度反应曲线发生偏移。这项研究提供了额外的证据，表明通过微生理测定法获得的药理学结果与通过更传统的功能测定法获得的结果一致。
