Kitanaka J, Maeda S, Baba A
Department of Pharmacology, Faculty of Pharmaceutical Sciences, Osaka University, Suita, Japan.
Neurochem Res. 1993 Feb;18(2):225-9. doi: 10.1007/BF01474688.
The effect of cytochalasin B on phosphoinositide (PI) hydrolysis was examined in rat hippocampal slices. Pretreatment of the slices with cytochalasin B caused a significant decrease in PI hydrolysis elicited by carbachol, norepinephrine, or by high K+. This effect was cytochalasin B dose- and time-dependent and was not mimicked by cytochalasin D, vinblastine, colchicine, or phloretin. In contrast, in [3H]inositol-prelabeled hippocampal membranes, cytochalasin B did not affect PI hydrolysis elicited by GTP gamma S and GTP gamma S plus carbachol. Similar result was obtained using the membranes prepared from the slices pretreated with cytochalasin B. The inhibitory effect of cytochalasin B on the carbachol-response was observed in SK-N-SH human neuroblastoma cells, but not in cultured rat astrocytes. These results indicate that cytochalasin B inhibits PI hydrolysis in neuron-specific manner and that its action may be an indirect cellular mechanism other than interaction with cytoskeleton elements.
在大鼠海马切片中研究了细胞松弛素B对磷酸肌醇（PI）水解的影响。用细胞松弛素B预处理切片会导致由卡巴胆碱、去甲肾上腺素或高钾离子引起的PI水解显著降低。这种作用具有细胞松弛素B剂量和时间依赖性，且细胞松弛素D、长春碱、秋水仙碱或根皮素无法模拟该作用。相反，在[3H]肌醇预标记的海马膜中，细胞松弛素B不影响由GTPγS以及GTPγS加卡巴胆碱引起的PI水解。使用经细胞松弛素B预处理的切片制备的膜也得到了类似结果。在SK-N-SH人神经母细胞瘤细胞中观察到了细胞松弛素B对卡巴胆碱反应的抑制作用，但在培养的大鼠星形胶质细胞中未观察到。这些结果表明，细胞松弛素B以神经元特异性方式抑制PI水解，其作用可能是一种不同于与细胞骨架成分相互作用的间接细胞机制。
