Effect of Voluntary Wheel Running on Striatal Dopamine Level and Neurocognitive Behaviors after Molar Loss in Rats

Socially interactive agents for robotic neurorehabilitation training: conceptualization and proof-of-concept study

Introduction

Individuals with diverse motor abilities often benefit from intensive and specialized rehabilitation therapies aimed at enhancing their functional recovery. Nevertheless, the challenge lies in the restricted availability of neurorehabilitation professionals, hindering the effective delivery of the necessary level of care. Robotic devices hold great potential in reducing the dependence on medical personnel during therapy but, at the same time, they generally lack the crucial human interaction and motivation that traditional in-person sessions provide.

Methods

To bridge this gap, we introduce an AI-based system aimed at delivering personalized, out-of-hospital assistance during neurorehabilitation training. This system includes a rehabilitation training device, affective signal classification models, training exercises, and a socially interactive agent as the user interface. With the assistance of a professional, the envisioned system is designed to be tailored to accommodate the unique rehabilitation requirements of an individual patient. Conceptually, after a preliminary setup and instruction phase, the patient is equipped to continue their rehabilitation regimen autonomously in the comfort of their home, facilitated by a socially interactive agent functioning as a virtual coaching assistant. Our approach involves the integration of an interactive socially-aware virtual agent into a neurorehabilitation robotic framework, with the primary objective of recreating the social aspects inherent to in-person rehabilitation sessions. We also conducted a feasibility study to test the framework with healthy patients.

Results and discussion

The results of our preliminary investigation indicate that participants demonstrated a propensity to adapt to the system. Notably, the presence of the interactive agent during the proposed exercises did not act as a source of distraction; instead, it positively impacted users' engagement.

Regulation of anxiety-like behaviors by S-palmitoylation and S-nitrosylation in basolateral amygdala

Protein posttranslational modification regulates synaptic protein stability, sorting and trafficking, and is involved in emotional disorders. Yet the molecular mechanisms regulating emotional disorders remain unelucidated. Here we report unknown roles of protein palmitoylation/nitrosylation crosstalk in regulating anxiety-like behaviors in rats. According to the percentages of open arm duration in the elevated plus maze test, the rats were divided into high-, intermediate- and low-anxiety groups. The palmitoylation and nitrosylation levels were detected by acyl-biotin exchange assay, and we found low palmitoylation and high nitrosylation levels in the basolateral amygdala (BLA) of high-anxiety rats. Furthermore, we observed that 2-bromopalmitate (2-BP), a palmitoylation inhibitor, induced anxiety-like behaviors, accompanied with decreased amplitude and frequency of mEPSCs and mIPSCs in the BLA. Additionally, we also found that inhibiting nNOS activity with 7-nitroindazole (7-NI) in the BLA caused anxiolytic effects and reduced the synaptic transmission. Interestingly, diazepam (DZP) rapidly elevated the protein palmitoylation level and attenuated the protein nitrosylation level in the BLA. Specifically, similar to DZP, the voluntary wheel running exerted DZP-like anxiolytic action, and induced high palmitoylation and low nitrosylation levels in the BLA. Lastly, blocking the protein palmitoylation with 2-BP induced an increase in protein nitrosylation level, and attenuating the nNOS activity by 7-NI elevated the protein palmitoylation level. Collectively, these results show a critical role of protein palmitoylation/nitrosylation crosstalk in orchestrating anxiety behavior in rats, and it may serve as a potential target for anxiolytic intervention.

The preconditioning effect of different exercise training modes on middle cerebral artery occlusion induced-behavioral deficit in senescent rats

Introduction

Brain abilities decrease after brain stroke in elderly. The neuroprotective effect of exercise training has been proved in clinical trials and animal experiment. Nevertheless, it is not still clear what kind of exercise has greater protective effect. The present study aimed at investigating pre-conditioning effect of endurance, resistance, and concurrent training on learning ability, anxiety, and spatial memory in aged rats following stroke strength with middle cerebral artery occlusion.

Method

We used 50 male Wistar rats (age = 24 months) that were assigned randomly in five groups; 1: sham group, 2: Control group 3: Endurance training 4: Resistance training, and 5: concurrent training. The exercise training groups received training for four weeks. Following training, middle cerebral artery occlusion was applied to induce cerebral ischemia. Using the elevated plus maze, shuttle box test, and Morris water maze, neurocognitive functions were tested in the sample rats.

Results

It was found that resistance training did not affect spatial memory in the acquisition phase, while concurrent training and endurance training enhanced spatial memory in the acquisition phase. On the contrary, spatial memory was improved by resistance training in the retention phase, while concurrent and endurance exercises did not affect spatial memory in the retention phase. Passive avoidance learning ability at acquisition phase was more in resistance group compared to the endurance and concurrent training in shuttle box test, but in retention phase was similar between training groups. Unlike endurance and concurrent training, resistance training reduced anxiety in senescent rats.

Conclusion

All three exercise types alleviated aversive learning and memory impairment induced by stroke in senescent rats. Notably, the resistance training showed a greater protective effect compared to the other two training methods.

Effects of Phoenix dactylifera against Streptozotocin-Aluminium Chloride Induced Alzheimer's Rats and Their In Silico Study

Phoenix dactylifera is known for medicinal importance due to its antioxidant, antidiabetic, antidepressant, and anti-inflammatory properties. This study is aimed at evaluating the effect of P. dactylifera seeds to cure Alzheimer's disease (AD). AD was induced in the rats with streptozotocin + aluminium chloride followed by treatment of methanolic extract of P. dactylifera seeds. The blood glucose levels were determined at regular intervals, which showed a prominent decrease in the extracts treated group. Behavior tests, including the Elevated Plus Maze (EPM) test and Morris Water Maze (MWM) test, were used to evaluate memory patterns in rats. The results indicated that extract-treated rats significantly improved memory behavior compared to the diseased group. After dissection, the serum electrolytes, antioxidant enzymes, and choline esterase enzymes were measured in different organs. The serum parameters creatinine, urea, and bilirubin increased after extract treatment. Similarly, the level of antioxidant enzymes like peroxidases (POD), glutathione (GSH), catalase (CAT), superoxide dismutase (SOD), and thiobarbituric acid reactive substance (TBARS) in the extract-treated group showed improved results that were close to the normal control group. The enzyme (lipase, insulin, amylase, and acetylcholine) levels were found enhanced in extract groups as compared to diseased rats. High-performance liquid chromatography (HPLC) was used to determine the level of dopamine and serotonin neurotransmitters, which were increased significantly for P. dactylifera seeds with values of 0.18 μg/mg tissue and 0.56 μg/mg tissue, respectively. Overall, results showed that P. dactylifera seeds proved to be quite efficient in improving the memory and behavior of treated rats. The antioxidants and enzymes were also increased; therefore, it may be a potential candidate for treating AD.

Exercise on Striatal Dopamine Level and Anxiety-Like Behavior in Male Rats after 2-VO Cerebral Ischemia

The purpose of this study was to discuss the effect of voluntary wheel running on striatal dopamine levels and anxiety-like behavior in rats with global cerebral ischemia. The male Sprague-Dawley rats were signed on in this study and randomly divided into following 4 groups: Control group (C group), Sham group (S group), ischemia group (I group), and 3 weeks physical exercise before ischemia group (3RI group). The rats in the 3RI group were placed in a voluntary running wheel for three weeks to exercise. Then, the rats in I and 3RI groups received bilateral carotid artery ligation (2-VO) operation. The C and S group did not perform voluntary running exercise and the bilateral common carotid arteries of S group were exposed without ligation. In vivo microdialysis was used in conjunction with high performance liquid chromatography (HPLC) and electrochemical detection to ascertain the level of dopamine in the striatum. Elevated plus maze (EPM) and open field (OF) were used to test anxiety status at 24 hours and 7days after 2-VO cerebral ischemia. Meanwhile, gait and motor coordination evaluations were carried out to eliminate the influence of non-specific motor problems. The results indicated that cerebral ischemia instigate the increase of striatal dopamine in I group rats during acute cerebral ischemia. A 3-week voluntary wheel running significantly enhances the striatal dopamine before ischemia and obstructs a further increase of dopamine during acute cerebral ischemia in 3RI group rats. At 24 hours after ischemia, striatal dopamine returned to pre-ischemic levels in 3RI group. Striatal dopamine in I group were less than pre-ischemic levels at 7 days. Behavioral data indicated that 3-week voluntary wheel running promoted recovery of anxiety-like behavior and gait were not affected by 2-VO cerebral ischemia at 24 hours post-ischemia rats. Therefore, it can be concluded that 3-week physical exercise significantly increased the striatal dopamine and improved anxiety-like behavior by inhibiting the increase of dopamine during acute cerebral ischemia and suppressing the decrease of dopamine after 24 hours and 7 days cerebral ischemia.

A red nucleus-VTA glutamate pathway underlies exercise reward and the therapeutic effect of exercise on cocaine use

Physical exercise is rewarding and protective against drug abuse and addiction. However, the neural mechanisms underlying these actions remain unclear. Here, we report that long-term wheel-running produced a more robust increase in c-fos expression in the red nucleus (RN) than in other brain regions. Anatomic and functional assays demonstrated that most RN magnocellular portion (RNm) neurons are glutamatergic. Wheel-running activates a subset of RNm glutamate neurons that project to ventral tegmental area (VTA) dopamine neurons. Optogenetic stimulation of this pathway was rewarding, as assessed by intracranial self-stimulation and conditioned place preference, whereas optical inhibition blocked wheel-running behavior. Running wheel access decreased cocaine self-administration and cocaine seeking during extinction. Last, optogenetic stimulation of the RNm-to-VTA glutamate pathway inhibited responding to cocaine. Together, these findings indicate that physical exercise activates a specific RNm-to-VTA glutamatergic pathway, producing exercise reward and reducing cocaine intake.

Different Exercise Time on 5-HT and Anxiety-like Behavior in the Rat With Vascular Dementia

BACKGROUND

Previous studies have demonstrated that pre-exercise suppresses anxiety-like behavior, but the effects of different exercise times on vascular dementia induced anxiety-like behavior have not been well investigated.

OBJECTIVE

The present study aims to investigate the underlying neurochemical mechanism of different pre-vascular-dementia exercise times on 5-HT and anxiety-like behavior in rats with vascular dementia.

METHODS

32 Sprague-Dawley (SD) rats were randomly divided into 4 groups: sham group (S group, n = 8), vascular dementia group (VD group, n = 8), 1-week physical exercise and vascular dementia group (1WVD group, n = 8), and 4 weeks physical exercise and vascular dementia group (4WVD group, n = 8). 1 week and 4 weeks of voluntary wheel running were used as pre-exercise training. The vascular dementia model was established by bilateral common carotid arteries occlusion (BCCAo) for 1 week. But bilateral common carotid arteries were not ligated in the sham group. The level of hippocampal 5-HT was detected with in vivo microdialysis coupled with high-performance liquid chromatography (MD-HPLC). Elevated plus maze (EPM), open field (OF), and light/dark box test were used to test anxiety-like behavior.

RESULTS

Compared with the C group, the hippocampal 5-HT was significantly decreased in the VD group after 1 week of ligated operation. The hippocampal 5-HT levels in 1WVD and 4WVD groups were substantially higher than the level in the VD group. The hippocampal 5-HT level has no significant difference among C, 1WVD, and 4WVD. Behavioral data suggested that the rats in the VD group developed obvious anxiety-like behavior after 1 week of ligation surgery. Still, the rats in 1WVD and 4WVD groups did not show significant anxiety-like behavior.

CONCLUSION

Both 1 week and 4 weeks of voluntary running wheel exercise can inhibit the anxiety-like behavior in rats with vascular dementia by upregulating 5-HT levels in the hippocampus in the VD model.

Exercise preconditioning ameliorates cognitive impairment and anxiety-like behavior via regulation of dopamine in ischemia rats

Cognitive impairment and anxiety are common health problems in acute ischemic stroke patients. Meanwhile, dopamine in the striatal brain region is significantly increased during the acute phase of cerebral ischemia. Besides, the studies shown that striatum and change of striatal dopamine are associated with learning and memory and anxiety. Further, physical exercise has been shown to improve neurocognitive and emotional function in animal models and patients with cerebral ischemia. However, the exact mechanism underlying this effect is unclear. The purpose of this research is to explore the effect of pre-ischemic voluntary wheel running on levels of striatal dopamine, cognition and anxiety in cerebral ischemia rats.

METHODS

48 adult male Sprague-Dawley rats were enrolled in this study and divided randomly in following 6 groups: sham group (S group, n = 8), ischemia group (I group, n = 8), 1 week wheel running group (1R group), 4 weeks wheel running group (4R group), 1 week pre-ischemia wheel running group (1RI group, n = 8) and 4 weeks pre-ischemia wheel running group (4RI group, n = 8). After training, cerebral ischemia was induced by permanent bilateral common carotid artery ligation (2-VO) operation. Microdialysis was used to collect dialysates from the striatum immediately from 30 min before ischemia to 90 min after ischemia. High-performance liquid chromatography-electrochemical detection system (HPLC) was used to determine the content of dopamine in the dialysates. Passive avoidance and elevated plus maze test were used to test neurocognitive function 24 h after 2-VO cerebral ischemia.

RESULTS

As compare with the constant striatal dopamine level of S group, the striatal dopamine level in I group after ischemia showed a trend of rapid increasing and reached maximum value at the 20 min (P<0.001), then decreased gradually. The striatal dopamine level in 1RI and 4RI group showed the trend were similar to I group, but the increasing magnitude was attenuated. A comparison of the basal striatal dopamine level in 4 groups found that the basal dopamine level in 1RI and 4RI group were higher than S and I group (P<0.001). In passive avoidance task, the retention latency of I group was significantly shorter than S group (P<0.001), and the retention latency of the 1RI, 1R and 4R, 4RI group were longer than I group (P<0.001), there was no significant difference in S, 1RI, 1R, 4R and 4RI group (P>0.05). In elevated plus maze test, the time and entrance numbers of open arms in I group were significantly less than S group (P<0.05), but these indices were no significant difference in S, 1RI, 1R, 4RI and 4RI group.

CONCLUSION

According to our results, 1 or 4 weeks pre-ischemia wheel running can significantly increase the basal dopamine level, attenuate the increase of striatal dopamine induced by cerebral ischemia and improve neurocognitive function in ischemia rats.

Differential effects of chronic voluntary wheel-running on morphine induced brain stimulation reward, motor activity and striatal dopaminergic activity

Physical exercise could be a protective factor against the development of substance use disorders; however, a number of preclinical studies report reward-enhancing effects of exercise for various drugs of abuse. We examined the effects of chronic wheel-running on brain reward sensitivity, reaction to novelty, reward-facilitating and locomotor-stimulating effects of morphine, using the intracranial self-stimulation (ICSS) and the open field test (OFT). Male Sprague-Dawley rats were randomly assigned to a sedentary or exercised group. For the ICSS procedure, rats were implanted with electrodes and trained to respond for electrical stimulation. Several indices were recorded in the training phase to estimate brain reward sensitivity. Once responding was stable, the animals of both groups received systemic injections of morphine and their ICSS thresholds were measured with the curve-shift paradigm. Employing the OFT, basal and morphine-induced locomotor activity was measured. Finally, basal and morphine-evoked tissue levels of dopamine and its metabolites were determined in the striatum using gas chromatography/mass spectrometry. Chronic wheel-running decreased brain reward sensitivity and subsequently increased the reward-facilitating effect of morphine. Exercised animals demonstrated a decreased reaction to novelty and reduced morphine-induced locomotion. Lastly, dopaminergic activity was decreased in the striatum of exercised animals under basal conditions, whereas morphine administration led to an increase in dopamine turnover. These findings indicate that chronic voluntary exercise exerts divergent effects on reward function, psychomotor activity and the reward-facilitating and locomotor-activating effects of opioids during adulthood. Our results provide insights into the increased non-medical use of opioids among young athletes reported in the literature.

Neuroprotective effect of different physical exercises on cognition and behavior function by dopamine and 5-HT level in rats of vascular dementia

The aim of the present study is to evaluate neuroprotective effect of different physical exercises on cognition and behavior function by dopamine and 5-HT in rats of vascular dementia. Forty Sprague-Dawley rats were enrolled in this study and randomly divided into following 5 groups: control group (C group, n = 8), vascular dementia group (VD group, n = 8), treadmill exercise and vascular dementia group (TE-VD group, n = 8), in-voluntary exercise and vascular dementia group (IE-VD group, n = 8), voluntary exercise and vascular dementia group (VE-VD group, n = 8). The rats in TE-VD, IE-VD and VE-VD groups were received different physical exercise interventions, treadmill exercise, voluntary running exercise, involuntary running exercise respectively, total 4 weeks. Next, the rats in VE-VD, IE-VD, TE-VD and VD groups were received bilateral common carotids arteries operation to create vascular dementia model. Then, we use a passive avoid test to evaluate cognition and open field test to evaluate cognition autonomic activity in each group. The level in hippocampal dopamine and 5-HT were detected by microdialysis coupled with high performance liquid chromatography. Behavior results demonstrated that: compared with C group, the cognition in VD group significantly decreased (p < 0.001); compared with VD group, the cognition in VE-VD, IE-VD and TE-VD groups were significantly increased (p < 0.001). However, there are no significant difference between VE-VD, IE-VD and TE-VD groups (p> 0.05). In addition, hippocampal dopamine and 5-HT level significantly decreased in VD group when compared with C group (p < 0.001); hippocampal dopamine and 5-HT level in VE-VD, IE-VD and TE-VD groups were significantly increased when compared with VD group (p < 0.05). However, there are no significant difference between VE-VD, IE-VD and TE-VD groups (p> 0.05). Therefore, we concluded that different physical exercises, included treadmill exercise, in-voluntary exercise and voluntary exercise, all can protect cognition by up-regulate dopamine and 5-HT level in rats of vascular dementia.

Voluntary exercise modulates learning & memory and synaptic plasticity impairments in sleep deprived female rats

Previous studies have indicated that forced exercise plays a preventive role in synaptic plasticity deficits in the hippocampus and behavioral impairments in sleep-deprived male and female rats. The objective of the present study was to evaluate the effects of voluntary exercise on early long-term potentiation (E-LTP) at the Cornu Ammonis (CA1) area of the hippocampus and behavioral functions by barnes maze and novel location tests in sleep-deprived female rats. Intact female Wistar rats were used in the present study. The exercise protocol was four weeks wheel running and the multiple platform method was applied to induce 72 h Sleep deprivation (SD). We examine the effect of exercise and/or SD on synaptic plasticity using in vivo extracellular recording in the CA1 area of the hippocampus. Spatial learning and memory examined by Barnes maze and recognition memory assessed by novel location test. Field potential recording indicated that the induction and maintenance phase of E-LTP impaired in the sleep deprived animals compared to the other groups. After 72 h SD, LTP impairments were reduced by 4 weeks of voluntary exercise but do not go back to control values. SD impairs learning and memory and exercise could improve these deficits. In conclusion, the synaptic plasticity deficit in sleep-deprived female rats was improved by voluntary exercise. Further studies are suggested to evaluate the possible underlying mechanisms.

Exercise-Induced Neuroprotection and Recovery of Motor Function in Animal Models of Parkinson's Disease

Parkinson's disease (PD) is manifested by progressive motor, autonomic, and cognitive disturbances. Dopamine (DA) synthesizing neurons in the substantia nigra (SN) degenerate, causing a decline in DA level in the striatum that leads to the characteristic movement disorders. A disease-modifying therapy to arrest PD progression remains unattainable with current pharmacotherapies, most of which cause severe side effects and lose their efficacy with time. For this reason, there is a need to seek new therapies supporting the pharmacological treatment of PD. Motor therapy is recommended for pharmacologically treated PD patients as it alleviates the symptoms. Molecular mechanisms behind the beneficial effects of motor therapy are unknown, nor is it known whether such therapy may be neuroprotective in PD patients. Due to obvious limitations, human studies are unlikely to answer these questions; therefore, the use of animal models of PD seems indispensable. Motor therapy in animal models of PD characterized by the loss of dopaminergic neurons has neuroprotective and neuroregenerative effects, and the completeness of neuronal protection may depend on (i) degree of neuronal loss, (ii) duration and intensity of exercise, and (iii) time elapsed between insult and commencing of training. As the physical activity is neuroprotective for dopaminergic neurons, the question arises what is the mechanism of this protective action. A current hypothesis assumes a central role of neurotrophic factors in the neuroprotection of dopaminergic neurons, even though it is still not clear whether increased DA level in the nigrostriatal axis results from neurogenesis of dopaminergic neurons in the SN, recovery of the phenotype of dopaminergic neurons, increased sprouting of the residual dopaminergic axons in the striatum, or generation of local striatal neurons from inhibitory interneurons. In the present review, we discuss studies describing the influence of physical exercise on the PD-like changes manifested in animal models of the disease and focus our interest on the current state of knowledge on the mechanism of neuroprotection induced by physical activity as a supportive therapy in PD.