اثر آنتاگونيست اوركسين-1 در هسته پاراونتريكولار تالاموس بر بيان ژن Camk2a در هيپوكمپ رت پس از القا ترجيح مكان شرطي شده مورفين

Background an‎d Objective: Learning an‎d memory are fundamental cognitive processes that play a central role in shaping complex behaviors an‎d facilitating adaptation to the environment. Disruption of these processes can lead to widespread consequences. Calcium/calmodulin-dependent protein kinase II alpha (CaMKIIα) is a key component of synaptic plasticity an‎d the molecular mechanisms underlying memory, while the orexin system has also gained increasing attention for its role in regulating cognitive functions. The present study aimed to investigate the regulatory effect of the orexin-1 receptor antagonist (SB-334867) in the paraventricular nucleus of the thalamus (PVT) on the expression of the Camk2a gene in the hippocampus of male rats. Materials an‎d Methods: This study used hippocampal tissue samples obtained from male rats that had previously undergone behavioral protocols (including morphine-induced conditioned place preference) an‎d pharmacological interventions (including intra-PVT administration of the orexin-1 receptor antagonist SB-334867). The expression of the Camk2a gene in these tissue samples was eva‎luated using real-time PCR. Results: The findings showed that morphine administration alone led to a significant increase in Camk2a gene expression in the hippocampus compared to the control (saline) group. Administration of the orexin-1 receptor antagonist (SB-334867) alone resulted in a significant decrease in the expression of this gene relative to the control group. In the groups that received both morphine an‎d the orexin-1 antagonist, Camk2a expression was significantly reduced compared to the morphine group. This indicates that SB-334867 was able to counteract the effect of morphine an‎d return the gene expression level to baseline, such that the expression in this group was not significantly different from the control (saline) group. Conclusion: These findings highlight the complex role of the orexin system an‎d the orexin-1 receptor in the PVT in molecular pathways associated with learning an‎d memory—particularly CaMKIIα in the hippocampus. The present results offer new insights into the neuro-molecular interactions underlying neural plasticity an‎d may contribute to a deeper understan‎ding of learning an‎d memory processes, as well as the potential for new pharmacological targets in this field.

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