Displaying publications 1 - 20 of 24 in total

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  1. Narayanan SN, Kumar RS, Kumar N, Prabhakar P, Nayak SB, Bhat PG
    Behav Brain Res, 2025 Mar 12;481:115424.
    PMID: 39788457 DOI: 10.1016/j.bbr.2025.115424
    Whilst the world sees the tremendous growth of mobile phone technology, radiofrequency electromagnetic radiation (RF-EMR) induced possible health effects have emerged as a topic of recent day debate. The current study is designed to test the hypothesis that chronic 900 MHz radiation exposure would potentially dysregulate the stress response system (HPA axis) in vivo, via, its non-thermal mechanisms, leading to alterations in the microarchitecture of the adrenal gland, vulnerable brain regions such as the hippocampus which may results in altered behaviours in rats. Male albino Wistar rats aged four weeks, weighing 50-60 g were subjected to 900 MHz radiation from a mobile phone for four weeks at a rate of one hour per day. On the 29th day, animals from the control, sham exposed and RF-EMR exposed groups were tested for contextual fear conditioning. They were later euthanized to study hippocampal and adrenal gland cytoarchitecture. Bright and dark compartment transitions in the avoidance box were considerably elevated in the RF-EMR exposed group and they exhibited a significant decrease in the latency to enter the dark compartment during the contextual fear conditioning test. Apoptosis was apparent in the CA3 region and perivascular space was significantly increased in the hippocampus of the radiation-exposed group. In addition to lymphocytic infiltrates, congested sinusoids, apoptotic-like changes were evident in the zona fasciculata of the adrenal gland. However, the cytoarchitecture of the adrenal medulla was comparable in all three groups. Chronic RF-EMR exposure caused changes in contextual fear conditioning, enlargement of hippocampal perivascular space, apparent CA3 apoptosis, and apoptotic-like changes in the zona fasciculata of the adrenal gland in rats.
    Matched MeSH terms: Avoidance Learning/physiology; Avoidance Learning/radiation effects
  2. Abu Bakar N, Mohd Sata NS, Ramlan NF, Wan Ibrahim WN, Zulkifli SZ, Che Abdullah CA, et al.
    Neurotoxicol Teratol, 2017 Jan-Feb;59:53-61.
    PMID: 27919701 DOI: 10.1016/j.ntt.2016.11.008
    Chronic exposure to mercury (Hg) can lead to cumulative impairments in motor and cognitive functions including alteration in anxiety responses. Although several risk factors have been identified in recent year, little is known about the environmental factors that either due exposure toward low level of inorganic mercury that may led to the developmental disorders. The present study investigated the effects of embryonic exposure of mercury chloride on motor function and anxiety-like behavior. The embryo exposed to 6 different concentrations of HgCl2 (7.5, 15, 30, 100, 125, 250nM) at 5hpf until hatching (72hpf) in a semi-static condition. The mortality rate increased in a dose dependent manner where the chronic embryonic exposure to 100nM decreased the number of tail coiling, heartbeat, and swimming activity. Aversive stimulus was used to examine the effects of 100nM interferes with the development of anxiety-related behavior. No elevation in both thigmotaxis and avoidance response of 6dpf larvae exposed with 100nM were found. Biochemical analysis showed HgCl2 exposure affects proteins, lipids, carbohydrates and nucleic acids of the zebrafish larvae. These results showed that implication of HgCl2 on locomotor and biochemical defects affects motor performance and anxiety-like responses. Yet, the potential underlying mechanisms these responses need to be further investigated which is crucial to prevent potential hazards on the developing organism due to neurotoxicant exposure.
    Matched MeSH terms: Avoidance Learning/drug effects*
  3. Vollala VR, Upadhya S, Nayak S
    Bratisl Lek Listy, 2011;112(12):663-9.
    PMID: 22372329
    The aim of this study was to evaluate the learning and memory-enhancing effect of Bacopa monniera in neonatal rats.
    Matched MeSH terms: Avoidance Learning/drug effects*
  4. Narayanan SN, Kumar RS, Paval J, Nayak S
    Bratisl Lek Listy, 2010;111(5):247-52.
    PMID: 20568412
    In the current study we evaluated adverse effects of monosodium glutamate (MSG) on memory formation and its retrieval as well as the role of ascorbic acid (Vitamin-C) in prevention of MSG-induced alteration of neurobehavioral performance in periadolescent rats.
    Matched MeSH terms: Avoidance Learning/drug effects
  5. Cherian SB, Bairy KL, Rao MS
    Indian J Exp Biol, 2009 Nov;47(11):893-9.
    PMID: 20099462
    With a view to examine the effect of chronic maternal stress on cognitive function in the offspring during young age, pregnant Wistar rats were subjected to restraint stress from embryonic day 11 till delivery. Male and female pups born to these stressed rats were subjected to passive avoidance test on postnatal day 30 and 31. Results were compared with rats of the same age and sex born to control mothers, which were not stressed. The results showed that prenatal maternal restraint stress impairs the memory retention during young age in both sexes. The memory retention deficit induced by maternal restraint stress was evident in the decreased latency to enter the dark compartment of passive avoidance apparatus by the rats born to stressed mothers. The observed behavioral deficit may be due to the insult of stress on the developing hippocampus, a structure of the brain concerned with learning and memory. The results suggest that prolonged prenatal stress leads to long lasting malfunction in the behavioral development during young age in both male and female young rats. However when compared to their respective stress naïve controls, it seems evident that prenatal restraint stress has a less effect on females which could be due to their oesterogenic effects. These data reinforce the view that prenatal stress affects cognitive development in a sex-specific manner.
    Matched MeSH terms: Avoidance Learning*
  6. Narayanan SN, Kumar RS, Potu BK, Nayak S, Bhat PG, Mailankot M
    Ups. J. Med. Sci., 2010 May;115(2):91-6.
    PMID: 20095879 DOI: 10.3109/03009730903552661
    The interaction of mobile phone radio-frequency electromagnetic radiation (RF-EMR) with the brain is a serious concern of our society.
    Matched MeSH terms: Avoidance Learning/radiation effects*
  7. Saffari M, Huang CH, Huang PC, Chang YH, Chen JS, Poon WC, et al.
    J Behav Addict, 2025 Mar 28;14(1):289-303.
    PMID: 39853322 DOI: 10.1556/2006.2024.00083
    BACKGROUND AND AIMS: There are limited data regarding associations between gaming disorder and physical activity (PA). The present study investigated the direct association between these two variables and assessed the potentially mediating roles of PA avoidance and two types of weight stigma (i.e., internalized weight stigma and perceived weight stigma) in the association.

    METHODS: An online cross-sectional survey that assessed PA avoidance, two types of weight stigma, and PA level was completed in late 2023 by 884 Taiwanese young adults aged between 20 and 40 years (63.9% females). Multinomial logistic regression and structural equation modeling (SEM) were used to assess the associations between variables and perform the mediation analysis.

    RESULTS: Cognitive behavioral symptoms and negative consequences related to gaming disorder were more common among participants with lower PA than those with moderate to high PA. Individuals at risk of gaming disorder exhibited higher level of PA avoidance, internalized weight stigma, and perceived weight stigma. The SEM found a direct association between gaming disorder and PA, which was negatively mediated by PA avoidance. However, this direct effect was not present when the association was negatively mediated by serial mediations of weight stigma and PA avoidance.

    DISCUSSION AND CONCLUSIONS: Higher gaming disorder was associated with higher levels of PA, but this association may not be present when taking into account the mediation effect of weight stigma and PA avoidance. The findings suggest complex relationships and further research is needed to examine individual differences and relationships among clinical groups.

    Matched MeSH terms: Avoidance Learning/physiology
  8. Shadin M, Barua MB, Ali T, Farahim F, Ripon M, Linkon MH, et al.
    Drug Dev Res, 2026 Nov;87(7):e70394.
    PMID: 42853217 DOI: 10.1002/ddr.70394
    Cholinergic dysfunction is a key feature of cognitive impairment, and currently available acetylcholinesterase (AChE) inhibitors provide limited symptomatic benefit and are often associated with adverse effects. This study evaluated the cognitive-protective effects of bavachin (BVC), a prenylated flavonoid from Psoralea corylifolia, and its interaction with Donepezil (DNP) in a scopolamine (SCP)-induced amnesia model. Male Swiss albino mice were pretreated with BVC (10-40 mg/kg), DNP (2.5 mg/kg), or their combination for 7 days prior to SCP challenge, followed by assessment using multiple behavioral paradigms, including novel object recognition, elevated plus maze, passive avoidance, Y-maze, and Morris water maze. BVC attenuated SCP-induced memory deficits in a dose-dependent manner, with the 40 mg/kg dose producing performance statistically comparable to, though not formally demonstrated to be equivalent to, the normal control across tests. Bliss independence analysis of behavioral endpoints indicated predominantly additive interactions, with occasional greater-than-additive trends. Biochemical evaluation demonstrated that BVC inhibits AChE in vitro (IC50 = 27.7 µM) and attenuates SCP-induced elevations of AChE activity ex vivo in the frontal cortex and hippocampus. Combination treatment showed a greater-than-additive interaction in the frontal cortex (ΔBliss = 0.054) and an approximately additive effect in the hippocampus (ΔBliss = 0.013). Molecular docking and molecular dynamics simulations further suggested stable binding of BVC within the active sites of AChE and butyrylcholinesterase (BChE). Collectively, these findings indicate that BVC attenuates cognitive deficits, at least in part, through cholinesterase inhibition, and exhibits additive effects with DNP, supporting its potential as an adjunctive candidate for cognitive disorders.
    Matched MeSH terms: Avoidance Learning/drug effects
  9. Savithri, N.V., Esa, R.
    Ann Dent, 2008;15(1):27-32.
    MyJurnal
    Dental fear is a hindrance to the effective provision of oral health care and causes patients to delay, or even avoid necessary care altogether. The aim of this study was to determine the prevalence and level of dental fear, to identify specific fear provoking stimuli and also to explore the avoidance behaviour among the respondents. A cross-sectional study was conducted on a sample of 407 antenatal mothers utilizing the Kleinknecht's Dental Fear Survey Questionnaire. The overall prevalence of dental fear was 94.1% of which 67.6% of the subjects reported low fear levels, 26.5% were moderately fearful while none were highly fearful. Only 5.9% of the subjects reported no fear. The drill and anaesthetic needle were identified as the most fear provoking objects. Subjects with moderate fear were about 6.4 times (OR=6.39; 95%CI 3.81-10.75) more likely to avoid making appointments and 6 times (OR=6.05; 95% CI 3.20-11.50) more likely to cancel appointments compared to subjects with lower levels of fear. This. study indicates that dental fear is a common problem among antenatal mothers contributing to poor dental attendance.
    Matched MeSH terms: Avoidance Learning
  10. Wong N, Lee CY
    J Econ Entomol, 2010 Oct;103(5):1754-60.
    PMID: 21061976
    The aim of our study was to investigate the intra- and interspecific agonistic behaviors exhibited by the worker and soldier castes of the subterranean termite Microcerotermes crassus Snyder (Isoptera: Termitidae). Aggression between M. crassus colonies from different field locations and also against three termite species--Coptotermes gestroi (Wasmann), Globitermnes sulphureus Haviland, and Odontotermes sp.--were observed in the laboratory. Termite responses were tested in paired combination of castes (soldiers versus soldiers, soldiers versus workers, and workers versus workers) consisting of 10 individuals each. Significant agonistic behaviors were observed only in encounters between pairings of different termite species. M. crassus was aggressive toward individuals from different species but not toward individuals from different M. crassus colonies. Mortality of M. crassus reached 100% in most of the interspecific encounters. However, no or low mortality was recorded in the intraspecific pairings.
    Matched MeSH terms: Avoidance Learning
  11. Ghanbari A, Zibara K, Salari S, Ghareghani M, Rad P, Mohamed W, et al.
    CNS Neurol Disord Drug Targets, 2018;17(7):528-538.
    PMID: 29968547 DOI: 10.2174/1871527317666180703111643
    BACKGROUND & OBJECTIVE: The adolescent brain has a higher vulnerability to alcoholinduced neurotoxicity, compared to adult's brain. Most studies have investigated the effect of ethanol consumption on the body, however, methanol consumption, which peaked in the last years, is still poorly explored.

    METHOD: In this study, we investigated the effects of methanol neurotoxicity on memory function and pathological outcomes in the hippocampus of adolescent rats and examined the efficacy of Light- Emitting Diode (LED) therapy. Methanol induced neurotoxic rats showed a significant decrease in the latency period, in comparison to controls, which was significantly improved in LED treated rats at 7, 14 and 28 days, indicating recovery of memory function. In addition, methanol neurotoxicity in hippocampus caused a significant increase in cell death (caspase3+ cells) and cell edema at 7 and 28 days, which were significantly decreased by LED therapy. Furthermore, the number of glial fibrillary acid protein astrocytes was significantly lower in methanol rats, compared to controls, whereas LED treatment caused their significant increase. Finally, methanol neurotoxicity caused a significant decrease in the number of brain-derived neurotrophic factor (BDNF+) cells, but also circulating serum BDNF, at 7 and 28 days, compared to controls, which were significantly increased by LED therapy. Importantly, LED significantly increased the number of Ki-67+ cells and BDNF levels in the serum and hypothalamus in control-LED rats, compared to controls without LED therapy.

    CONCLUSION: In conclusion, chronic methanol administration caused severe memory impairments and several pathological outcomes in the hippocampus of adolescent rats which were improved by LED therapy.

    Matched MeSH terms: Avoidance Learning/drug effects; Avoidance Learning/radiation effects
  12. Damodaran T, Tan BWL, Liao P, Ramanathan S, Lim GK, Hassan Z
    J Ethnopharmacol, 2018 Oct 05;224:381-390.
    PMID: 29920356 DOI: 10.1016/j.jep.2018.06.020
    ETHNOPHARMACOLOGICAL RELEVANCE: Clitoria ternatea L. (CT), commonly known as Butterfly pea, is used in Indian Ayurvedic medicine to promote brain function and treat mental disorders. Root of CT has been proven to enhance memory, but its role in an animal model of chronic cerebral hypoperfusion (CCH), which has been considered as a major cause of brain disorders, has yet to be explored.

    AIM OF THE STUDY: To assess the motor and cognitive effects of acute oral administration of CT root methanolic extract and hippocampal long-term plasticity in the CA1 region of the CCH rat model.

    MATERIALS AND METHODS: Male Sprague Dawley rats (200-300 g) were subjected to permanent bilateral occlusion of common carotid arteries (PBOCCA) or sham operation. Then, these rats were given oral administration of CT root extract at doses of 100, 200 or 300 mg/kg on day 28 post-surgery and tested using behavioural tests (open-field test, passive avoidance task, and Morris water maze) and electrophysiological recordings (under urethane anaesthesia).

    RESULTS: Treatment with CT root extract at the doses of 200 and 300 mg/kg resulted in a significant enhancement in memory performance in CCH rats induced by PBOCCA. Furthermore, CCH resulted in inhibition of long-term potentiation (LTP) formation in the hippocampus, and CT root extract rescued the LTP impairment. The CT root extract was confirmed to improve the glutamate-induced calcium increase via calcium imaging using primary cultured rat neurons. No significance difference was found in the CaMKII expression. These results demonstrated that CT root extract ameliorates synaptic function, which may contribute to its improving effect on cognitive behaviour.

    CONCLUSIONS: Our findings demonstrated an improving effect of CT root extract on memory in the CCH rat model suggesting that CT root extract could be a potential therapeutic strategy to prevent the progression of cognitive deterioration in vascular dementia (VaD) and Alzheimer's disease (AD) patients.

    Matched MeSH terms: Avoidance Learning/drug effects
  13. Sivalingam M, Ogawa S, Parhar IS
    Sci Rep, 2020 11 11;10(1):19569.
    PMID: 33177592 DOI: 10.1038/s41598-020-76287-9
    The habenula is an evolutionarily conserved brain structure, which has recently been implicated in fear memory. In the zebrafish, kisspeptin (Kiss1) is predominantly expressed in the habenula, which has been implicated as a modulator of fear response. Hence, in the present study, we questioned whether Kiss1 has a role in fear memory and morphine-induced fear memory impairment using an odorant cue (alarm substances, AS)-induced fear avoidance paradigm in adult zebrafish, whereby the fear-conditioned memory can be assessed by a change of basal place preference (= avoidance) of fish due to AS-induced fear experience. Subsequently, to examine the possible role of Kiss1 neurons-serotonergic pathway, kiss1 mRNA and serotonin levels were measured. AS exposure triggered fear episodes and fear-conditioned place avoidance. Morphine treatment followed by AS exposure, significantly impaired fear memory with increased time-spent in AS-paired compartment. However, fish administered with Kiss1 (10-21 mol/fish) after morphine treatment had significantly lower kiss1 mRNA levels but retained fear memory. In addition, the total brain serotonin levels were significantly increased in AS- and Kiss1-treated groups as compared to control and morphine treated group. These results suggest that habenular Kiss1 might be involved in consolidation or retrieval of fear memory through the serotonin system.
    Matched MeSH terms: Avoidance Learning/drug effects
  14. Nasir MN, Habsah M, Zamzuri I, Rammes G, Hasnan J, Abdullah J
    J Ethnopharmacol, 2011 Mar 24;134(2):203-9.
    PMID: 21167268 DOI: 10.1016/j.jep.2010.12.010
    Centella asiatica has a reputation to restore declining cognitive function in traditional medicine. To date, only a few compounds that show enhancing learning and memory properties are available. Therefore, the present study investigates the effects of for acute administration of asiatic acid (A-A) isolated from Centella asiatica administration on memory and learning in male Spraque-Dawley rats.
    Matched MeSH terms: Avoidance Learning/drug effects*
  15. Chidambaram SB, Pandian A, Sekar S, Haridass S, Vijayan R, Thiyagarajan LK, et al.
    Environ Toxicol, 2016 Dec;31(12):1955-1963.
    PMID: 26434561 DOI: 10.1002/tox.22196
    PURPOSE: Present study was undertaken to evaluate the antiamnesic effect of Sesamum indicum (S. indicum) seeds (standardized for sesamin, a lignan, content) in scopolamine, a muscarinic antagonist intoxicated mice.

    METHODS: Male Swiss albino mice (18-22 g bw) were pretreated with methanolic extract of sesame seeds (MSSE) (100 and 200 mg/kg/day, p.o) for a period of 14 days. Scopolamine (0.3 mg/kg, i.p.) was injected on day 14, 45 ± 10 min after MSSE administration. Antiamnesic effect of MSSE was evaluated using step-down latency (SDL) on passive avoidance apparatus and transfer latency (TL) on an elevated plus maze. To unravel the mechanism of action, we examined the effects of MSSE on the genes such as acetyl cholinesterase (AChE), muscarinic receptor M1 subtype (mAChRM1 ), and brain derived neurotrophic factor (BDNF) expression within hippocampus of experimental mice. Further, its effects on bax and bcl-2 were also evaluated. Histopathological examination of hippocampal CA1 region was performed using cresyl violet staining.

    RESULTS: MSSE treatment produced a significant and dose dependent increase in step down latency in passive avoidance test and decrease in transfer latency in elevated plus maze in scopolamine intoxicated injected mice. MSSE down-regulated AChE and mAChRM1 and up-regulated BDNF mRNA expression. Further, it significantly down-regulated the bax and caspase 3 and up-regulated bcl-2 expression in scopolamine intoxicated mice brains. Mice treated with MSSE showed increased neuronal counts in hippocampal CA1 region when compared with scopolamine-vehicle treated mice.

    CONCLUSION: Sesame seeds have the ability to interact with cholinergic components involved in memory function/restoration and also an interesting candidate to be considered for future cognitive research. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1955-1963, 2016.

    Matched MeSH terms: Avoidance Learning/drug effects
  16. Cheung JPY, Cheung PWH, Chiu CK, Chan CYW, Kwan MK
    Asian Spine J, 2019 Feb;13(1):45-55.
    PMID: 30326696 DOI: 10.31616/asj.2018.0135
    STUDY DESIGN: Surgeon survey.

    PURPOSE: To study the various surgical practices of different surgeons in the Asia-Pacific region.

    OVERVIEW OF LITERATURE: Given the diversity among Asia-Pacific surgeons, there is no clear consensus on the preferred management strategies for cervical myelopathy. In particular, the role of prophylactic decompression for silent cervical spinal stenosis is under constant debate and should be addressed.

    METHODS: Surgeons from the Asia-Pacific Spine Society participated in an online questionnaire comprising 50 questions. Data on clinical diagnosis, investigations and outcome measures, approach to asymptomatic and silent cervical spinal stenosis, guidelines for surgical approach, and postoperative immobilization were recorded. All parameters were analyzed by the Mantel-Haenszel test.

    RESULTS: A total of 79 surgeons from 16 countries participated. Most surgeons used gait disturbance (60.5%) and dyskinetic hand movement (46.1%) for diagnosis. Up to 5.2% of surgeons would operate on asymptomatic spinal stenosis, and 18.2% would operate on silent spinal stenosis. Among those who would not operate, most (57.1%) advised patients on avoidance behavior and up to 9.5% prescribed neck collars. For ossification of the posterior longitudinal ligament (OPLL), anterior removal was most commonly performed for one-level disease (p<0.001), whereas laminoplasty was most commonly performed for two- to four-level disease (p=0.036). More surgeons considered laminectomy and fusion for multilevel OPLL. Most surgeons generally preferred to use a rigid neck collar for 6 weeks postoperatively (p<0.001).

    CONCLUSIONS: The pooled recommendations include prophylactic or early decompression surgery for patients with silent cervical spinal stenosis, particularly OPLL. Anterior decompression is primarily suggested for one- or two-level disease, whereas laminoplasty is preferred for multilevel disease.

    Matched MeSH terms: Avoidance Learning
  17. Andy SN, Pandy V, Alias Z, Kadir HA
    Life Sci, 2018 Aug 01;206:45-60.
    PMID: 29792878 DOI: 10.1016/j.lfs.2018.05.035
    AIM: Neuroinflammation is a critical pathogenic mechanism of most neurodegenerative disorders especially, Alzheimer's disease (AD). Lipopolysaccharides (LPS) are known to induce neuroinflammation which is evident from significant upsurge of pro-inflammatory mediators in in vitro BV-2 microglial cells and in vivo animal models. In present study, we investigated anti-neuroinflammatory properties of deoxyelephantopin (DET) isolated from Elephantopus scaber in LPS-induced neuroinflammatory rat model.

    MATERIALS AND METHODS: In this study, DET (0.625. 1.25 and 2.5 mg/kg, i.p.) was administered in rats for 21 days and those animals were challenged with single injection of LPS (250 μg/kg, i.p.) for 7 days. Cognitive and behavioral assessment was carried out for 7 days followed by molecular assessment on brain hippocampus. Statistical significance was analyzed with one-way analysis of variance followed by Dunnett's test to compare the treatment groups with the control group.

    KEY FINDINGS: DET ameliorated LPS-induced neuroinflammation by suppressing major pro-inflammatory mediators such as iNOS and COX-2. Furthermore, DET enhanced the anti-inflammatory cytokines and concomitantly suppressed the pro-inflammatory cytokines and chemokine production. DET treatment also reversed LPS-induced behavioral and memory deficits and attenuated LPS-induced elevation of the expression of AD markers. DET improved synaptic-functionality via enhancing the activity of pre- and post-synaptic markers, like PSD-95 and SYP. DET also prevented LPS-induced apoptotic neurodegeneration via inhibition of PARP-1, caspase-3 and cleaved caspase-3.

    SIGNIFICANCE: Overall, our studies suggest DET can prevent neuroinflammation-associated memory impairment and neurodegeneration and it could be developed as a therapeutic agent for the treatment of neuroinflammation-mediated and neurodegenerative disorders, such as AD.

    Matched MeSH terms: Avoidance Learning/drug effects
  18. Mani V, Parle M, Ramasamy K, Abdul Majeed AB
    J Sci Food Agric, 2011 Jan 15;91(1):186-92.
    PMID: 20848667 DOI: 10.1002/jsfa.4171
    Coriandrum sativum L., commonly known as coriander and belonging to the family Apiaceae (Umbelliferae), is cultivated throughout the world for its nutritional value. The present study was undertaken to investigate the effects of fresh Coriandrum sativum leaves (CSL) on cognitive functions, total serum cholesterol levels and brain cholinesterase activity in mice. In this study, CSL (5, 10 and 15% w/w of diet) was fed orally with a specially prepared diet for 45 days consecutively to experimental animals. Elevated plus-maze and passive avoidance apparatus served as the exteroceptive behavioral models for testing memory. Diazepam, scopolamine and ageing-induced amnesia served as the interoceptive behavioral models.
    Matched MeSH terms: Avoidance Learning/drug effects
  19. Yusoff NH, Suhaimi FW, Vadivelu RK, Hassan Z, Rümler A, Rotter A, et al.
    Addict Biol, 2016 Jan;21(1):98-110.
    PMID: 25262913 DOI: 10.1111/adb.12185
    Mitragynine is the major psychoactive alkaloid of the plant kratom/ketum. Kratom is widely used in Southeast Asia as a recreational drug, and increasingly appears as a pure compound or a component of 'herbal high' preparations in the Western world. While mitragynine/kratom may have analgesic, muscle relaxant and anti-inflammatory effects, its addictive properties and effects on cognitive performance are unknown. We isolated mitragynine from the plant and performed a thorough investigation of its behavioural effects in rats and mice. Here we describe an addictive profile and cognitive impairments of acute and chronic mitragynine administration, which closely resembles that of morphine. Acute mitragynine has complex effects on locomotor activity. Repeated administration induces locomotor sensitization, anxiolysis and conditioned place preference, enhances expression of dopamine transporter- and dopamine receptor-regulating factor mRNA in the mesencephalon. While there was no increase in spontaneous locomotor activity during withdrawal, animals showed hypersensitivity towards small challenging doses for up to 14 days. Severe somatic withdrawal signs developed after 12 hours, and increased level of anxiety became evident after 24 hours of withdrawal. Acute mitragynine independently impaired passive avoidance learning, memory consolidation and retrieval, possibly mediated by a disruption of cortical oscillatory activity, including the suppression of low-frequency rhythms (delta and theta) in the electrocorticogram. Chronic mitragynine administration led to impaired passive avoidance and object recognition learning. Altogether, these findings provide evidence for an addiction potential with cognitive impairments for mitragynine, which suggest its classification as a harmful drug.
    Matched MeSH terms: Avoidance Learning/drug effects
  20. Parsi S, Pandamooz S, Heidari S, Naji M, Morfini G, Ahmadiani A, et al.
    Neuroscience, 2015 Jan 22;284:99-106.
    PMID: 25270904 DOI: 10.1016/j.neuroscience.2014.09.045
    Alzheimer's disease (AD) is characterized by progressive and irreversible cognitive and memory impairment. The discovery of familial forms of AD (fAD) in association with specific gene mutations facilitated the generation of numerous rodent models. These models in turn proved valuable for the study of molecular mechanisms underlying AD pathogenesis, and facilitated translational research and preclinical drug development. This study aimed to introduce a new rat model of AD simulating some aspects of the sporadic cases of disease.
    Matched MeSH terms: Avoidance Learning
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