McCann D J, Su T P
Neurochemistry Unit, National Institute on Drug Abuse, Baltimore, MD 21224.
Neurosci Lett. 1992 Jul 20;141(2):239-42. doi: 10.1016/0304-3940(92)90903-k.
Tris-HCl is the most commonly used buffer in studies of radioligand binding to sigma receptors, with concentrations as high as 50 or 100 mM often used. We report here that these concentrations of Tris substantially inhibit (+)-[3H]SKF-10,047 binding to sigma receptors. The well-established inhibitory effect of Tris-HCl on ligand binding to PCP receptors did not contribute to the presently reported inhibition of (+)-[3H]SKF-10,047 binding. The IC50 of Tris, determined in the presence of 10 mM potassium phosphate buffer, was 15.4 +/- 1.2 mM (n = 3, pH 8.0, 25 degrees C, 1 nM radioligand). Equilibrium saturation studies revealed an apparent competitive inhibition of binding.
在放射性配体与σ受体结合的研究中，Tris-HCl是最常用的缓冲液，其浓度常常高达50或100 mM。我们在此报告，这些浓度的Tris会显著抑制(+)-[³H]SKF-10,047与σ受体的结合。Tris-HCl对配体与PCP受体结合的既定抑制作用并非目前所报告的(+)-[³H]SKF-10,047结合抑制的原因。在10 mM磷酸钾缓冲液存在下测定的Tris的IC50为15.4±1.2 mM（n = 3，pH 8.0，25℃，1 nM放射性配体）。平衡饱和研究揭示了明显的竞争性结合抑制。
