Chronic intranasal oxytocin alleviates cognitive impairment and reverses oxytocin signaling upregulation in MK801-induced mice.

OBJECTIVE: Cognitive impairment, especially impaired social cognition, is largely responsible for the deterioration of the social life of patients with schizophrenia (SZ). Oxytocin (OT) is a neuropeptide that offers promising therapy for SZ. This study aimed to explore whether OT could affect dizocilpine (MK801)-induced cognitive impairment and to investigate the effect of exogenous OT on the endogenous OT system in the hippocampus. METHODS: The SZ mouse model was established by repeated administration of dizocilpine [MK801, 0.6 mg/kg, intraperitoneal (i.p.)], and then OT (6-60 µg/kg, intranasal) or risperidone (0.3 mg/kg, i.p.) was administered to explore the effect of OT on cognitive impairment. RESULTS: OT at a dose of 6 µg/kg alleviated MK801-induced hyperactivity, sociability impairment, and spatial memory impairment. OT at a dose of 20 or 60 µg/kg attenuated the hyperactivity and social novelty impairment. In MK801-injected mice, the compensatory upregulation of OT mRNA in the hippocampus was reversed by three OT doses, whereas 60 µg/kg OT reversed the compensatory upregulation of CD38 protein expression. CONCLUSION: OT alleviated cognitive impairment in the SZ mouse model to varying degrees, reversing the compensatory upregulation of OT signaling in the hippocampus.

Environmental fate of microplastics in alpine and canyon-type river-cascade reservoir systems: Large-scale investigation of the Yalong River in the eastern Qinghai-Tibet Plateau.

Reservoirs are regarded as potential collection sites for microplastics (MPs), and ample water resources in plateau regions provide favorable natural conditions for hydroelectric power generation. However, research on the impact of cascade reservoir construction in the plateau region on the fate of MPs within the watershed is limited. In this study, the Yalong River, an alpine canyon river in the eastern Qinghai-Tibet Plateau, was selected as the research area. This study explored the distribution of MPs at various depths in water, sediment, and riverbank soil as well as the formation of "MP communities" within the river-cascade reservoir system. Furthermore, the effects of dam construction on MPs' migration in different environments were analyzed. The results revealed that the abundance of MPs in the water and sediment within the cascade reservoir area (CRA) was significantly higher than that in the river area (RA) (P < 0.001). Additionally, the trend of increasing MPs in water with decreasing altitude was notably slower in CRA. Regarding shape, the proportion of fibers in the water within the CRA was significantly lower than that in the RA, with a smaller vertical migration rate in the water than in the sediment. The proportion of MPs < 500 µm in the water within the CRA was significantly higher than that in the RA. High-density MPs were notably deposited in the reservoir sediments. The analysis of the MP communities revealed that the construction of cascade dams led to relative geographical isolation between different sampling sites, reducing the similarity of MP communities in the CRA. This study established a theoretical foundation for understanding the impact of cascade dam construction on the fate characteristics of MPs and their potential risks in plateau areas.