Cytochalasin B inhibits phosphoinositide hydrolysis in rat hippocampal slices.
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.
Department of Pharmacology, Faculty of Pharmaceutical Sciences, Osaka University, Suita, Japan.
J
J
Kitanaka
S
S
Maeda
A
A
Baba
D000818:Animals; D002478:Cells, Cultured; D003571:Cytochalasin B / Q000494:pharmacology*; D003599:Cytoskeleton / Q000187:drug effects* / Q000378:metabolism; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism; D006868:Hydrolysis; D066298:In Vitro Techniques; D008297:Male; D010716:Phosphatidylinositols / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
D010716:Phosphatidylinositols; D003571:Cytochalasin B