The aquaporin-4 inhibitor, N-(1,3,4-thiadiazol-2-yl)-3-pyridinecarboxamide, inhibits the glymphatic system

Background and objectives

Aquaporin-4 (AQP4) plays a crucial role in the glymphatic system and is vital for maintaining homeostasis in the central nervous system. This study aimed to investigate the effects of N-(1,3,4-thiadiazol-2-yl)-3-pyridinecarboxamide (TGN-020), a selective AQP4 inhibitor, on glymphatic function and to assess its impact on short-term behavior in mice.

Methods

In this laboratory study, mice were randomly assigned to TGN-020-treated and control groups. We evaluated glymphatic function by measuring the distribution of Evans blue dye in the brain following injection into the cisterna magna. Behavioral assessment of cognitive function was performed using open field and Morris water maze tests. AQP4 protein expression levels were analyzed via immunohistochemistry. Statistical comparisons were conducted using the one-way analysis of variance to evaluate the results among groups.

Results

Our findings revealed that the areas of Evans blue dye in the dorsal (p < 0.001) and ventral (p < 0.001) surfaces of the brain were significantly reduced in the TGN-020 group compared to the control group, indicating impaired glymphatic function. However, behavioral tests demonstrated no significant short-term changes; the mean distance traveled in the open field was 4,345 cm in the control group and 4,049 cm in the TGN-020 group (p = 0.5625), while the mean speed was 2.649 cm/s for controls and 2.868 cm/s for the TGN-020 group (p = 0.6762). In the Morris water maze, latency was comparable (36.33 s for TGN-020 vs. 34.89 s for controls, p = 0.758). Additionally, no significant differences in AQP4 expression intensity were observed between the two groups.

Conclusions

Our study demonstrates that acute inhibition of AQP4 through a single dose of TGN-020 significantly impairs glymphatic function without inducing short-term behavioral abnormalities in mice. These findings contribute to understanding AQP4’s role in the glymphatic system and its potential implications for neurological function.

Keywords

Aquaporin-4 inhibitor, TGN-020, AQP4, Glymphatic system, Anaesthetic-induced behaviour change, Sevoflurane

Full text:

https://www.xiahepublishing.com/2472-0712/ERHM-2024-00029

The study was recently published in the Exploratory Research and Hypothesis in Medicine.

Exploratory Research and Hypothesis in Medicine (ERHM) publishes original exploratory research articles and state-of-the-art reviews that focus on novel findings and the most recent scientific advances that support new hypotheses in medicine. The journal accepts a wide range of topics, including innovative diagnostic and therapeutic modalities as well as insightful theories related to the practice of medicine. The exploratory research published in ERHM does not necessarily need to be comprehensive and conclusive, but the study design must be solid, the methodologies must be reliable, the results must be true, and the hypothesis must be rational and justifiable with evidence.

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