Knight A R, Bowery N G
Department of Pharmacology, School of Pharmacy, London, United Kingdom.
J Neural Transm Suppl. 1992;35:189-96. doi: 10.1007/978-3-7091-9206-1_13.
We have used the technique of autoradiography to study the binding of [3H]-GABA to GABAA and GABAB receptors in brains taken from rats that are genetically predisposed to petit mal type seizures. A range of concentrations of [3H]-GABA were employed to test the hypothesis that this predisposition was due to regional changes in either the number of GABAA or GABAB receptors, or affinity of GABA for these receptors. We found no statistical difference in the levels of radioligand binding to GABAA and GABAB receptors in animals susceptible to seizures compared to control animals in any of the brain regions studied over the concentration range 25 nM to 400 nM. This indicated that there was no change in either the Kd (affinity) or Bmax (receptor number) in these animals and that the pharmacological basis for the efficacy of GABAB antagonists in this seizure condition probably lies elsewhere.
我们运用放射自显影技术，研究了[3H]-γ-氨基丁酸（GABA）与遗传性易患失神发作型癫痫大鼠脑内GABAA和GABAB受体的结合情况。采用一系列浓度的[3H]-GABA来检验这一假说，即这种易患性是由于GABAA或GABAB受体数量的区域变化，或者是GABA对这些受体的亲和力变化所致。在25 nM至400 nM的浓度范围内，我们发现在任何所研究的脑区中，与对照动物相比，易患癫痫动物中放射性配体与GABAA和GABAB受体的结合水平没有统计学差异。这表明这些动物的解离常数（Kd，亲和力）或最大结合容量（Bmax，受体数量）均未发生变化，并且GABAB拮抗剂在这种癫痫病症中发挥疗效的药理学基础可能在其他方面。
