Büch H P, Altmayer P, Büch U
Institut für Pharmakologie und Toxikologie, Universität des Saarlandes Homburg/Saar, FRG.
Acta Anaesthesiol Scand. 1990 Jan;34(1):35-40. doi: 10.1111/j.1399-6576.1990.tb03037.x.
In vitro thiopental binding (substrate concentration 0.04.10(-3) M = 10 micrograms/ml) to 1% human serum albumin (HSA) increased significantly from 40.2% (= control) to 47.3% in the presence of 1.18.10(-3) M = 2.84 vol% halothane. A 4-fold higher halothane concentration (4.71.10(-3) M) had an even greater effect with an increase in the thiopental fraction bound to 55.5%. With a constant HSA concentration (1% or 5%) and thiopental concentrations in the range 0.01-1.5.10(-3) M or 0.01-0.38.10(-3) M, respectively, the halothane effect (increase in thiopental binding) was always evident, as well as in other experiments with constant thiopental concentration (0.04.10(-3) M) and variation in the HSA concentration (0.5-10%). Two classes of binding sites for thiopental were apparent at the HSA molecule. In the control experiments the following binding parameters were found: n1 = 0.01, k1 = 181.10(3) M-1; n2 = 45.73, k2 = 0.08.10(3) M-1, K = 5.47.10(3) M-1. In the presence of halothane the binding parameters changed as follows: n1 = 0.14, k1 = 29.4.10(3) M-1; n2 = 11.68, k2 = 0.42.10(3) M-1, K = 9.02.10(3) M-1.
在体外，硫喷妥钠（底物浓度0.04×10⁻³ M = 10微克/毫升）与1%人血清白蛋白（HSA）的结合在1.18×10⁻³ M = 2.84体积%氟烷存在的情况下，从40.2%（=对照）显著增加到47.3%。氟烷浓度高4倍（4.71×10⁻³ M）时效果更明显，与硫喷妥钠结合的部分增加到55.5%。在HSA浓度恒定（1%或5%）且硫喷妥钠浓度分别在0.01 - 1.5×10⁻³ M或0.01 - 0.38×10⁻³ M范围内时，氟烷的作用（硫喷妥钠结合增加）总是很明显，在其他硫喷妥钠浓度恒定（0.04×10⁻³ M）且HSA浓度变化（0.5 - 10%）的实验中也是如此。在HSA分子上可明显看出两类硫喷妥钠结合位点。在对照实验中发现以下结合参数：n1 = 0.01，k1 = 181×10³ M⁻¹；n2 = 45.73，k2 = 0.08×10³ M⁻¹，K = 5.47×10³ M⁻¹。在氟烷存在的情况下，结合参数变化如下：n1 = 0.14，k1 = 29.4×10³ M⁻¹；n2 = 11.68，k2 = 0.42×10³ M⁻¹，K = 9.02×10³ M⁻¹。
