The phosphatidylinositol-3 kinase/Akt pathway mediates geranylgeranylacetone-induced neuroprotection against cerebral infarction in rats.

Previous studies demonstrated the cytoprotective effect of geranylgeranylacetone (GGA), a heat shock protein inducer, against ischemic insult. Phosphatidylinositol-3 kinase/Akt (PI3K/Akt) is thought to be an important factor that mediates neuroprotection. However, the signaling pathways in the brain in vivo after oral GGA administration remain unclear. We measured and compared infarction volumes to investigate the effect of GGA on cerebral infarction induced by permanent middle cerebral artery occlusion in rats. We evaluated the effects of pretreatment with 5-hydroxydecanoate (5HD), a specific mitochondrial ATP-sensitive potassium (mitoK(ATP)) channel inhibitor; diazoxide (DZX), a selective mitoK(ATP) channel opener and wortmannin (Wort), a specific PI3K inhibitor of GGA-induced neuroprotection against infarction volumes. To clarify the relationship between PI3K/Akt activation and neuroprotection, we used immunoblot analysis to determine the amount of p-Akt proteins present after GGA administration with or without Wort treatment. Neuroprotective effects of GGA (pretreatment with a single oral GGA dose (800 mg/kg) 48 h before ischemia) were prevented by 5HD, DZX and Wort pretreatment, which indicates that the selective mitoK(ATP) channel and the PI3K/Akt pathway may mediate GGA-dependent protection. Oral GGA-induced p-Akt and GGA pretreatment enhanced ischemia-induced p-Akt, both of which were prevented by Wort pretreatment. These results suggest that a single oral dose of GGA induces p-Akt and that GGA plays an important role in neuroprotection against cerebral ischemia through the mitoK(ATP) channel opening.

Abe E ，Fujiki M ，Nagai Y ，Shiqi K ，Kubo T ，Ishii K ，Abe T ，Kobayashi H ... -  《-》

A Single Oral Dose of Geranylgeranylacetone Upregulates Vascular Endothelial Growth Factor and Protects against Kainic Acid-Induced Neuronal Cell Death: Involvement of the Phosphatidylinositol-3 Kinase/Akt Pathway.

Previous studies demonstrated the cytoprotective effect of geranylgeranylacetone (GGA), a heat shock protein inducer, against ischemic insult or kainic acid (KA)-induced neuronal cell death. Phosphatidylinositol-3 kinase (PI3K)/Akt is thought to be an important factor that mediates neuroprotection. However, the signaling pathways in the brain in vivo after oral GGA administration remain unclear. We measured and compared hippocampal neuron density to investigate the effect of GGA on KA-induced cell death in rats. We evaluated the effects of pretreatment with wortmannin (Wort), a specific PI3K inhibitor, on GGA-induced neuroprotection against KA-induced cell death. To clarify the relationship between PI3K/Akt activation and neuroprotection, we used immunoblot analysis to determine the amounts of p-Akt and vascular endothelial growth factor (VEGF) proteins present after GGA administration with or without Wort treatment. Neuroprotective effects of GGA (pretreatment with a single oral dose of GGA, 800 mg/kg, 48 h before KA injection) were prevented by Wort pretreatment, which indicates that the selective PI3K/Akt pathway may mediate the GGA-dependent protection. Oral GGA-induced p-Akt and VEGF, and GGA pretreatment enhanced KA-induced VEGF, both of which were prevented by Wort pretreatment. These results suggest that a single oral dose of GGA induces p-Akt and that GGA plays an important role in neuroprotection against KA-induced neuronal cell death through VEGF induction.

Kawasaki Y ，Fujiki M ，Uchida S ，Morishige M ，Momii Y ，Ishii K ... -  《-》

Geranylgeranylacetone, a noninvasive heat shock protein inducer, induces protein kinase C and leads to neuroprotection against cerebral infarction in rats.

Uchida S ，Fujiki M ，Nagai Y ，Abe T ，Kobayashi H ... -  《NEUROSCIENCE LETTERS》

Electroconvulsive seizure-induced VEGF is correlated with neuroprotective effects against cerebral infarction: Involvement of the phosphatidylinositol-3 kinase/Akt pathway.

The present study demonstrates the cytoprotective effect of electrical convulsive stimulation (ECS) as a potential neuroprotective vascular endothelial growth factor (VEGF) inducer against ischemic insult. Phosphatidylinositol-3 kinase/Akt (PI3K/Akt) is thought to be an important factor that mediates neuroprotection. However, the signaling pathways in the brain in vivo after ECS remain unclear. We measured and compared infarction volumes to investigate the effect of ECS on cerebral infarction induced by permanent middle cerebral artery occlusion in rats. We evaluated the effects of pretreatment with Wortmannin (Wort), a specific PI3K inhibitor of ECS-induced neuroprotection against infarction volumes. To clarify the relationship between PI3K/Akt activation and neuroprotection, we used immunoblot analysis to determine the amounts of p-Akt and VEGF proteins present after ECS with or without Wort treatment. Neuroprotective effects of ECS (pretreatment with a single ECS 6h before ischemia) were prevented by Wort pretreatment, which indicates that the PI3K/Akt pathway may mediate ECS-dependent protection. ECS induced p-Akt and VEGF and ECS pretreatment enhanced ischemia-induced VEGF, both of which were prevented by Wort pretreatment. These results suggest that a single ECS induces p-Akt and that ECS plays an important role in neuroprotection against the cerebral ischemia through VEGF induction.

Fujiki M ，Abe E ，Nagai Y ，Shiqi K ，Kubo T ，Ishii K ，Abe T ，Kobayashi H ... -  《-》

The role of phosphoinositide-3-kinase/Akt pathway in propofol-induced postconditioning against focal cerebral ischemia-reperfusion injury in rats.

Wang HY ，Wang GL ，Yu YH ，Wang Y ... -  《-》