Alzheimer-like changes in protein kinase B and glycogen synthase kinase-3 in rat frontal cortex and hippocampus after damage to the insulin signalling pathway
Version of Record online: 12 JAN 2006
Journal of Neurochemistry
Volume 96, Issue 4, pages 1005–1015, February 2006
How to Cite
Salkovic-Petrisic, M., Tribl, F., Schmidt, M., Hoyer, S. and Riederer, P. (2006), Alzheimer-like changes in protein kinase B and glycogen synthase kinase-3 in rat frontal cortex and hippocampus after damage to the insulin signalling pathway. Journal of Neurochemistry, 96: 1005–1015. doi: 10.1111/j.1471-4159.2005.03637.x
- Issue online: 26 JAN 2006
- Version of Record online: 12 JAN 2006
- Received July 8, 2005; revised manuscript received November 2, 2005; accepted November 2, 2005.
- Alzheimer's disease;
- glucose transporter 2;
- glycogen synthase kinase-3;
- protein kinase B;
The insulin-resistant brain state is related to late-onset sporadic Alzheimer's disease, and alterations in the insulin receptor (IR) and its downstream phosphatidylinositol-3 kinase signalling pathway have been found in human brain. These findings have not been confirmed in an experimental model related to sporadic Alzheimer's disease, for example rats showing a neuronal IR deficit subsequent to intracerebroventricular (i.c.v.) treatment with streptozotocin (STZ). In this study, western blot analysis performed 1 month after i.c.v. injection of STZ showed an increase of 63% in the level of phosphorylated glycogen synthase kinase-3α/β (pGSK-3α/β) protein in the rat hippocampus, whereas the levels of the unphosphorylated form (GSK-3α/β) and protein kinase B (Akt/PKB) remained unchanged. Three months after STZ treatment, pGSK-3α/β and Akt/PKB levels tended to decrease (by 8 and 9% respectively). The changes were region specific, as a different pattern was found in frontal cortex. Structural alterations were also found, characterized by β-amyloid peptide-like aggregates in brain capillaries of rats treated with STZ. Similar neurochemical changes and cognitive deficits were recorded in rats treated with i.c.v. 5-thio-d-glucose, a blocker of glucose transporter (GLUT)2, a transporter that is probably involved in brain glucose sensing. The IR signalling cascade alteration and its consequences in rats treated with STZ are similar to those found in humans with sporadic Alzheimer's disease, and our results suggest a role for GLUT2 in Alzheimer's pathophysiology.