Interaction of Dorsal Hippocampal Nicotinic Receptors and Zinc Oxide Nanoparticles on Memory Consolidation

Interaction of Dorsal Hippocampal Nicotinic Receptors and Zinc Oxide Nanoparticles on Memory Consolidation Background: Zinc oxide nanoparticles (ZnO NPs) are widely used in industry, medicine, and agriculture.Previous studies have shown that exposure to ZnO NPs can induce changes in learning and memory.Nicotinic receptors in the dorsal hippocampus are involved in druginduced effects on memory formation.Objectives: The present study investigates the possible role of dorsal hippocampal nicotinic receptors in the effects of ZnO NPs on memory consolidation.Methods: Animals were bilaterally cannulated in the CA1 regions of the hippocampus.Saline, nicotine, and mecamylamine (a non-selective antagonist of nicotinic acetylcholine receptors) were administered immediately after training (intracerebral), and intraperitoneal injections of saline or ZnO NPs were given at 5-min intervals.Memory and motor activity were assessed using the passive avoidance test and the open field test, respectively.Results: Post-training intra-CA1 microinjection of nicotine improved the amnesia induced by ZnO NPs.Mecamylamine potentiated the effects of an ineffective dose of ZnO NPs on memory consolidation. Conclusion:ZnO NPs impair memory through interactions with nicotinic receptors in the dorsal hippocampus.