scholarly journals Trigeminal Neuralgia Induced by Cobra Venom in the Rat Leads to Deficits in Abilities of Spatial Learning and Memory

2015 ◽  
Vol 2;18 (2;3) ◽  
pp. E207-E216
Author(s):  
Jian-xiong An

Background: Patients with chronic pain usually suffer from cognitive impairment, with memory deterioration being the most common deficit that affects daily functioning and quality of life. The causes for this impairment are not clear despite intensive clinical studies. Few studies have evaluated impaired learning using animal models of persistent pain. Objective: In this study, a new trigeminal neuralgia model induced by cobra venom was adopted to explore effects of chronic pain on spatial learning and memory in rats. Study Design: Controlled animal study. Setting: Department of Anesthesiology, Pain Medicine & Critical Care Medicine, Aviation General Hospital of China Medical University. Methods: Thirty adult male Sprague-Dawley rats were randomly divided into 2 groups (n = 15): NS control group and cobra venom group, 0.9% sterile saline or cobra venom solution was injected into the sheath of the infraorbital nerve (ION), respectively. The development of trigeminal neuralgia was accessed by changes in free behavioral activity 3 days before the surgery and 3, 7, 12, 20, and 30 days after the surgery to identify whether the model was successful or not. Morris water maze test determined the abilities of spatial learning and memory at the time points before the surgery, and 2 weeks and 5 weeks after the surgery. We also observed the ultrastructure of the ION and medulla oblongata of rats following 8 weeks of chronic trigeminal neuropathic pain. Results: Rats with the cobra venom injection displayed significantly more face grooming and fewer exploratory activities compared to the NS control group or baseline (P < 0.01). Both groups improved their latency to reach the platform with the largest difference on the first day (P < 0.01), but without memory deficits in a probe trial for the second water maze protocol. For the third water maze testing, the rats in the cobra venom group experienced decreased abilities of spatial learning and memory, a longer latency with spatial memory deficits during the probe trial (P < 0.05). At the ultrastructural level, we found changes in the medulla oblongata after cobra venom injection resulting in severe demyelination and loss of axons that might be implicated in the causes of cognitive deficits. Limitations: Limitations include partial vision loss in the eye on the lesion side of the rats that might be missed and the absence of evaluating the ultrastructural changes in other parts of the brain. Conclusions: The results of this study suggest that trigeminal neuralgia induced by cobra venom in adult rats can impair spatial learning and memory function over time and results in demonstrable changes in the ultrastructure of the medulla oblongata. This new animal model may be useful for future studies on the effect of chronic pain on learning and cognition. Key words: Cognitive deficits, memory deterioration, cobra venom, trigeminal neuralgia, electron microscopy

2017 ◽  
Vol 2 (20;2) ◽  
pp. 53-67
Author(s):  
Jianxiong An

Background: Chronic pain often results in cognitive impairment. Our previous study showed that trigeminal neuralgia induced by cobra venom leads to spatial learning and memory deficits, although the underlying mechanism remains unclear. However, recent evidence indicates that the c-AMP-responsive element binding protein (CREB)/brain derived neurotrophic factor (BDNF) pathway plays a critical role in various etiologies of cognitive deficits. Objectives: Our aim was to explore the CREB/BDNF pathway to determine the molecular mechanisms involved in the pathogenesis of cognitive impairment caused by cobra venominduced trigeminal neuralgia. Study Design: A randomized, controlled animal study. Setting: Department of Anesthesiology, Beijing Friendship Hospital, Capital Medical University. Methods: Fifty male Sprague–Dawley rats were randomly divided into 3 groups: cobra venom group, sham group, and control group. Cobra venom or saline was injected into the sheath of the infraorbital nerve (ION), respectively. Video recordings and mechanical thresholds were used to analyze changes in behavioral activity 3 days before surgery and 4, 7, 14, 21, 28, and 56 days after surgery. Morris water maze tests were conducted at 4- and 8-week time points after surgery to evaluate spatial learning and memory. We also investigated expression changes of phosphorylated CREB (p-CREB) and BDNF in the hippocampus and prefrontal cortex (PFC) using western blotting and immunohistochemistry. Results: Cobra venom-treated rats exhibited significant changes in face grooming, as well as exploratory and resting behaviors, compared with the control group and sham group (both P < 0.001). Rats in the cobra venom group exhibited slightly impaired acquisition (P < 0.05) without memory deficits (P > 0.05) in the first water maze protocol. In the second water maze test, rats in the cobra venom group exhibited spatial learning and memory deficits, with fewer platform site crossings during the probe trial (P < 0.05). Moreover, results showed decreased p-CREB and BDNF expressions in the hippocampus and PFC in the cobra venom group, with significant differences at 9 weeks post-surgery (P < 0.05). Limitations: No signaling inhibitor or genetic manipulation was administered to further confirm upstream factors of the CREB/BDNF pathway in cognitive deficits caused by chronic trigeminal neuralgia. Conclusions: The findings suggest that cognitive impairment caused by cobra venom-induced trigeminal neuralgia is associated with downregulation of the CREB/BDNF pathway in the hippocampus and PFC. Key words: Cognitive impairment, the CREB/BDNF pathway, cobra venom, trigeminal neuralgia, hippocampus, prefrontal cortex, free behavior, Morris water maze


Author(s):  
Asma Ulhusna Shaimi ◽  
Hasmah Abdullah ◽  
Zalina Ismail ◽  
Wan Amir Nizam Wan Ahmad

Dehydroepiandrosterone sulphate (DHEAS) is a neurosteroid that is found in greater concentration within the brain rather than in any other body organ (Corpechot et al., 1981) and studies have shown that in the brain, DHEAS has a role in enhancing both learning and memory (Markowski et.al., 2001). This present study investigated the relationship between DHEAS and spatial learning and memory in the rat hippocampus. Male Sprague-Dawley rats were divided into two groups and their spatial learning behaviour was evaluated with the Morris Water Maze. The intensity of DHEAS was simultaneously recorded in real time via the Fiber Fluorescence Microscopy (FFM) S-650 probe of the Cellvisio system. There were significant changes in the swimming pattern of the experimental groups obtained via the Morris Water Maze from day 1 until day 5 and day 6 for the probe test. Meanwhile, it was also seen that the intensity of DHEAS fluorescence increased in parallel to the swimming pattern of the experimental rats in comparison to the control group. The findings suggest that the changes in DHEAS fluorescence has a strong link to both spatial learning and memory.


Author(s):  
Narges Marefati ◽  
Amin Mokhtari-Zaer ◽  
Farimah Beheshti ◽  
Sareh Karimi ◽  
Zahra Mahdian ◽  
...  

Abstract Background Modulatory effects of soy extract and estradiol on the central nervous system (CNS) have been reported. The effect of soy on scopolamine-induced spatial learning and memory in comparison to the effect of estradiol was investigated. Materials and methods Ovariectomized rats were divided into the following groups: (1) control, (2) scopolamine (Sco), (3) scopolamine-soy 20 (Sco-S 20), (4) scopolamine-soy 60 (Sco-S 60), (5) scopolamine-estradiol 20 (Sco-E 20) and (6) scopolamine-estradiol 60 (Sco-E 60). Soy extract, estradiol and vehicle were administered daily for 6 weeks before training in the Morris water maze (MWM) test. Scopolamine (2 mg/kg) was injected 30 min before training in the MWM test. Results In the MWM, the escape latency and traveled path to find the platform in the Sco group was prolonged compared to the control group (p < 0.001). Treatment by higher doses of soy improved performances of the rats in the MWM (p < 0.05 – p < 0.001). However, treatment with both doses of estradiol (20 and 60 μg/kg) resulted in a statistically significant improvement in the MWM (p < 0.01 – p < 0.001). Cortical, hippocampal and serum levels of malondialdehyde (MDA), as an index of lipid peroxidation, were increased which was prevented by soy extract and estradiol (p < 0.001). Cortical, hippocampal as well as serum levels of the total thiol, superoxide dismutase (SOD) and catalase (CAT) in Sco group were lower than the control group (p < 0.001) while they were enhanced when the animals were treated by soy extract and estradiol (p < 0.01 – p < 0.001). Conclusions It was observed that both soy extract and estradiol prevented learning and memory impairments induced by scopolamine in ovariectomized rats. These effects can be attributed to their protective effects on oxidative damage of the brain tissue.


1990 ◽  
Vol 23 (5) ◽  
pp. 427-439 ◽  
Author(s):  
Richard C. Tees ◽  
Kristin Buhrmann ◽  
Jordan Hanley

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Nawel Yagoubi ◽  
Yosra Jomni ◽  
Mohsen Sakly

The aim of this study was to characterize a novel animal model hyperthermia-induced febrile seizure and to investigate the impacts of repetitive febrile seizures on spatial learning and memory performances in immature rats.Methods. Rats were subjected to hyperthermia exposure one, two, or three times in 10-day intervals during 30 min in a water bath warmed at 45–50°C and their behaviour was monitored. Morris water maze spatial learning and memory were examined for control and treated groups. Results showed that rats subjected to 30-minute hyperthermia hot water developed rapidly myoclonic jerks and then generalized seizures. After a single hyperthermia exposure, the time for generalised tonic-clonic seizures appearance was 16.08 ± 0.60 min and it decreased gradually with repetitive exposure to reach 12.46 ± 0.39 min by the third exposure. Febrile seizures altered the spatial learning and memory abilities in Morris water maze and increased the time spent to attain the platform after one or two exposures, while after a third exposure rats exhibited the same latency compared to controls. Similar results were obtained in probe test where rats, subjected to hyperthermia for one or two episodes, spent less time in the target quadrant compared to corresponding controls. Further, when platform was moved from northwest to southwest quadrant, memory transfer test indicated that after one or two hyperthermia exposures cognitive performances were slightly altered, while after a third exposure the latency to escape increased significantly compared to untreated group. It was concluded that 30 min of hyperthermia hot water was sufficient to induce febrile seizures in immature rats and an increase of susceptibility was observed with repetitive hyperthermia exposure. Hyperthermia treatment impaired cognitive performances but the effects were mostly transient and moderate.


2004 ◽  
Vol 25 (2) ◽  
pp. 223-229 ◽  
Author(s):  
Barbara Shukitt-Hale ◽  
John J. McEwen ◽  
Aleksandra Szprengiel ◽  
James A. Joseph

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Ning Ding ◽  
Jing Jiang ◽  
Menghan Lu ◽  
Jiatong Hu ◽  
Yiyuan Xu ◽  
...  

Objective. To investigate the effect of manual acupuncture (MA) on NLRP3 inflammasome-related proteins. Methods. SAMP8 mice were randomly divided into Alzheimer’s disease (AD) group, the MA group, and the medicine (M) group. Mice in the M group were treated with donepezil hydrochloride at 0.65 μg/g. In the MA group, MA was applied on Baihui (GV20) and Yintang (GV29) for 20 min and then pricked at Shuigou (GV26). The Morris water maze was applied to assess spatial learning and memory. Immunohistochemical staining and western blot analysis were used to observe the expression of NLRP3 inflammasome-related proteins. Results. Compared with the normal (N) control group, spatial learning and the memory capabilities of the AD group significantly decreased (p<0.01). The number of NLRP3, ASC, Caspase-1, and IL-1β positively stained cells in the AD group was higher than the N group, and the relative expression levels of the above proteins were significantly higher than those in the N group (p<0.01). These changes were reversed by both MA and donepezil (p<0.01). Conclusion. MA can improve the learning and memory capabilities of SAMP8 mice. The negative regulation of the NLRP3/Caspase-1 pathway in the hippocampus may be a possible mechanism of MA in the treatment of AD.


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