Neural oscillations as a bridge between glutamatergic system and emotional behaviors in simulated
Xueliang Shang1, Bo Xu1, Qun Li1
1College of Life Sciences, Key Laboratory of Bioactive Materials Ministry of Education and State Key Laboratory of Medicinal Chemical Biology, Nankai University, 300071 Tianjin, PR China.
Abstract:
This study aims to investigate if neural oscillations can play a role as a bridge between the alteration of glutamatergic system and emotional behaviors in simulated microgravity (SM) mice. Adult male C57BL/6J mice were randomly divided into two groups: SM and control groups. The animal model was established by hindlimb unloading (HU). The mice were exposed to HU continued for 14days. Weight and sucrose consumption were measured. The degree of anxious and depressive was evaluated by Open field test and Elevated plus maze test. Local field potentials were recorded in the hippocampal perforant path (PP) and dentate gyrus (DG) regions. The NMDAR2A/2B (NR2A/2B) subunits expression and glutamate level were measured by Western and high performance liquid chromatography (HPLC), respectively. After 14days, SM mice exhibited depressive-like and anxiety-like behaviors, while the expression of NR2A/2B subunits and the glutamate level were significantly decreased in the SM group. Moreover, the power distribution of theta (3-8Hz) was decreased by HU, which further significantly attenuated the identical-frequency strength of phase synchronization and the neural information flow at theta rhythm on the PP-DG pathway. The theta-gamma phase synchronization strength was also significantly reduced by HU. The data imply that the neural oscillations measurements is a sign of the emotional behaviors impairment and the glutamatergic system change induced by HU.
Insights
Simulated microgravity impairs emotional behaviors in mice by altering the glutamatergic system and reducing neural oscillations. These changes in neural activity, specifically theta rhythm, are linked to anxiety and depression-like symptoms.
Area of Science:
- Neuroscience
- Space Biology
Background:
- Spaceflight and simulated microgravity can induce behavioral changes.
- The glutamatergic system and neural oscillations are crucial for emotional regulation.
Purpose of the Study:
- To investigate the link between glutamatergic system alterations, neural oscillations, and emotional behaviors in simulated microgravity.
- To determine if neural oscillations serve as a bridge between glutamatergic changes and emotional deficits.
Main Methods:
- Adult male mice were subjected to hindlimb unloading (HU) for 14 days to simulate microgravity.
- Behavioral tests (Open Field, Elevated Plus Maze), electrophysiology (local field potentials), Western blot (NR2A/2B subunits), and HPLC (glutamate levels) were employed.
Main Results:
- Simulated microgravity mice showed increased anxiety and depression-like behaviors.
- Reduced expression of NMDAR2A/2B subunits and glutamate levels were observed in the simulated microgravity group.
- Theta (3-8Hz) neural oscillations, phase synchronization, and information flow in the hippocampal perforant path-dentate gyrus pathway were significantly decreased.
Conclusions:
- Neural oscillations, particularly theta rhythm, are impaired by simulated microgravity.
- These oscillatory changes correlate with emotional behavior deficits and glutamatergic system alterations.
- Neural oscillation measurements can indicate emotional and neurochemical changes induced by simulated microgravity.
