Escitalopram Ameliorates Tau Hyperphosphorylation and Spatial Memory Deficits Induced by Protein Kinase A Activation in Sprague Dawley Rats.

Abstract

Here, we investigated the effect of escitalopram pretreatment on protein kinase A (PKA)-induced tau hyperphosphorylation and spatial memory deficits in rats using western blot and behavioral tests, respectively. We demonstrated that escitalopram effectively ameliorated tau hyperphosphorylation and the spatial memory deficits induced by PKA activation. We measured the total and activity-dependent Ser9-phosphorylated levels of glycogen synthase kinase (GSK)-3β in hippocampal extracts. No significant change in the total level of GSK-3β was observed between the different groups. However, compared with forskolin injection alone, pretreatment with escitalopram increased the level of Ser9-phosphorylated GSK-3β. We also demonstrated that escitalopram increased Akt phosphorylation at Ser473 (the active form of Akt). Furthermore, we identified other important kinases and phosphatases, such as protein phosphatase 2A, extracellular signal-regulated kinases 1 and 2, and MAP kinase kinase-1/2, that have previously been reported to play a crucial role in tau phosphorylation; however, we did not detect any significant change in the activation of these kinases or phosphatases in our study. We unexpectedly demonstrated that forskolin caused anxiety-like behavior in rats, and pretreatment with escitalopram did not significantly ameliorate the anxiety-like behavior induced by forskolin. These data provide the first evidence that escitalopram ameliorates forskolin-induced tau hyperphosphorylation and spatial memory impairment in rats; these effects do not occur via the anti-anxiety activity of escitalopram but may involve the Akt/GSK-3β signaling pathway.

• Authors: Qing-Guo Ren, Yan-Juan Wang, Wei-Gang Gong, Lin Xu, Zhi-Jun Zhang
• Journal: Journal of Alzheimer's disease : JAD (J Alzheimers Dis) Vol. 47 Issue 1 Pg. 61-71 ( 2015) ISSN: 1875-8908 [Electronic] Netherlands
• PMID: 26402755 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antidepressive Agents, Second-Generation
• tau Proteins
• Citalopram
• Colforsin
• Serine
• GSK3B protein, human
• Glycogen Synthase Kinase 3 beta
• Gsk3b protein, rat
• Proto-Oncogene Proteins c-akt
• Glycogen Synthase Kinase 3

Topics

• Animals
• Antidepressive Agents, Second-Generation (therapeutic use)
• Citalopram (therapeutic use)
• Colforsin (toxicity)
• Disease Models, Animal
• Enzyme Activation (drug effects)
• Exploratory Behavior (drug effects)
• Food Preferences (drug effects)
• Glycogen Synthase Kinase 3 (metabolism)
• Glycogen Synthase Kinase 3 beta
• Male
• Maze Learning (drug effects)
• Memory Disorders (chemically induced)
• Mood Disorders (chemically induced, drug therapy)
• Proto-Oncogene Proteins c-akt (metabolism)
• Rats
• Rats, Sprague-Dawley
• Reaction Time (drug effects)
• Serine (metabolism)
• tau Proteins (metabolism)