Mimaki T, Suzuki Y, Tagawa T, Karasawa T, Yabuuchi H
Department of Pediatrics, Osaka University Medical School, Japan.
Med J Osaka Univ. 1990 Mar;39(1-4):19-22.
We previously reported that zonisamide inhibits both [3H]flunitrazepam and [3H]muscimol binding in rat brain. In the present study, [3H]zonisamide was found to bind in a saturable fashion to the crude synaptosomal fraction of whole rat brain. Linear regression analysis of the binding data in the Scatchard plot indicated a Kd of 90 nM, and a maximal binding capacity of 1.40 x 10(3) fmol/mg protein. Displacement studies revealed an inhibitory effect of clonazepam and an enhancement effect of GABA on specific [3H]zonisamide binding. These results suggest that specific [3H]zonisamide binding sites may have a tight correlationship with benzodiazepine receptors in rat brain.
我们之前报道过，唑尼沙胺可抑制大鼠脑中[3H]氟硝西泮和[3H]蝇蕈醇的结合。在本研究中，发现[3H]唑尼沙胺以可饱和的方式与全大鼠脑的粗突触体部分结合。Scatchard图中结合数据的线性回归分析表明，解离常数（Kd）为90 nM，最大结合容量为1.40×10³ fmol/mg蛋白质。置换研究显示，氯硝西泮具有抑制作用，γ-氨基丁酸（GABA）对特异性[3H]唑尼沙胺结合具有增强作用。这些结果表明，特异性[3H]唑尼沙胺结合位点可能与大鼠脑中的苯二氮䓬受体密切相关。
