Introduction: 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 known to be involved in drug-induced effects on memory formation. Aim: The present study aimed to investigate the possible role of dorsal hippocampal nicotinic receptors in the effects of ZnO NPs on memory consolidation. Methods: In this study, animals were bilaterally cannulated in the CA1 regions of the hippocampus. Saline, nicotine, and mecamylamine (a non-selective antagonist of nAChRs) were administered immediately after training (intracerebral), and intraperitoneal injections of saline or ZnO NPs were given at 5-minute intervals. Memory and motor activity were assessed using the passive avoidance test and the open field test, respectively. Results: showed that 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: These findings suggest that ZnO NPs impair memory through interactions with nicotinic receptors in the dorsal hippocampus.
