Scopolamine-Induced Memory Impairment in Mice: Effects of PEA-OXA on Memory Retrieval and Hippocampal LTP

Abstract

Transient global amnesia, both persistent and transient, is a very common neuropsychiatric syndrome. Among animal models for amnesia and testing new drugs, the scopolamine test is the most widely used for transient global amnesia (TGA). This study examined the scopolamine-induced deficits in working memory, discriminative memory, anxiety, and motor activity in the presence of intranasal PEA-OXA, a dual antagonist of presynaptic α2 and H3 receptors. Male C57BL/6 mice were treated with intraperitoneal scopolamine (1 mg/kg) with or without pre-treatment (15 min) or post-treatment (15 min) with intranasal PEA-OXA (10 mg/kg). It was seen that scopolamine induced deficits of discriminative and spatial memory and motor deficit. These changes were associated with a loss of synaptic plasticity in the hippocampal dentate gyrus: impaired LTP after lateral entorhinal cortex/perforant pathway tetanization. Furthermore, hippocampal Ach levels were increased while ChA-T expression was reduced following scopolamine administration. PEA-OXA either prevented or restored the scopolamine-induced cognitive deficits (discriminative and spatial memory). However, the same treatment did not affect the altered motor activity or anxiety-like behavior induced by scopolamine. Consistently, electrophysiological analysis showed LTP recovery in the DG of the hippocampus, while the Ach level and ChoA-T were normalized. This study confirms the neuroprotective and pro-cognitive activity of PEA-OXA (probably through an increase in the extracellular levels of biogenic amines) in improving transient memory disorders for which the available pharmacological tools are obsolete or inadequate and not directed on specific pathophysiological targets.

Basic, Translational, and Clinical Research on Dementia

“…Consistently, electrophysiological analysis has shown LTP recovery in the dentate gyrus of the hippocampus. Therefore, this study has confirmed the neuroprotective and pro-cognitive activity of PEA-OXA (probably through an increase in the extracellular levels of biogenic amines) in improving transient memory disorders, for which the available pharmacological tools are obsolete or inadequate and are not directed on specific pathophysiological targets [41].…”

“…Moreover, the domain of behavioral or neuropsychiatric symptoms has been found to be less investigated, thus prompting new prospective studies with homogeneous design [38] since the latter affect some 99% of patients over the course of the disease [39] and they are managed with potentially harmful antipsychotics [40]. Belardo et al [41] have attempted a preclinical approach to the development of novel non-pharmacological control of AD and associated neuropsychiatric symptoms. They investigated transient and persistent global amnesia which is a very common neuropsychiatric syndrome.…”