Atomoxetine Protects Against NMDA Receptor-mediated Hippocampal Neuronal Death Following Transient Global Cerebral Ischemia

Background: Atomoxetine has been widely used for the treatment of attention-deficit/ hyperactivity disorder. ATX has additional abilities such as antagonistic effects on the N-methyl-Daspartate receptors (NMDARs) and benefit effects in some animal models of neurological disorders. However, there were few studies regarding protective effects and related mechanisms of ATX against cerebral ischemic insults. Objective: The objective of this study is to investigate neuroprotection of ATX pretreatment and its mechanisms in the hippocampal cornu ammonis 1 (CA1) region following transient global cerebral ischemia in gerbils. Method: Gerbils were subjected to transient global cerebral ischemia induced by the occlusion of common carotid arteries for 5 min. Thirty mg/kg of ATX was administrated intraperitoneally once daily for 3 days before ischemic surgery. To examine neuroprotective effects of ATX, we carried out neuronal nuclear antigen immunohistochemistry and Fluoro-Jade B histofluorescence staining. In addition, immunoreactivities of NMDAR1, NMDAR2A/B, B-cell lymphoma 2 (Bcl-2) and Bcl-2- associated X protein (Bax) are closely related with neuroexcitotoxicity. Results: ATX pretreatment reduced ischemia-induced hyperactivity and protected CA1 pyramidal neurons from ischemia. Pretreatment with ATX significantly attenuated ischemia-induced increases of NMDAR1 and NMDAR2A/B immunoreactivities in the CA1 pyramidal neurons at early time following ischemia. In addition, significant ischemia-induced alterations of Bcl-2 and Bax immunoreactivities were not observed in the ATX-treated group following ischemia. Conclusion: These results show that pretreatment with ATX protected against ischemic neuronal via inhibition of ischemia-induced excitotoxicity at early time following transient global cerebral ischemia.