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  1. Fulltext Zebrafish as a Model for Epilepsy-Induced Cognitive Dysfunction: A Pharmacological, Biochemical and Behavioral Approach
    Kundap UP, Kumari Y, Othman I, Shaikh MF
    Front Pharmacol, 2017;8:515.
    PMID: 28824436 DOI: 10.3389/fphar.2017.00515
    Epilepsy is a neuronal disorder allied with distinct neurological and behavioral alterations characterized by recurrent spontaneous epileptic seizures. Impairment of the cognitive performances such as learning and memory is frequently observed in epileptic patients. Anti-epileptic drugs (AEDs) are efficient to the majority of patients. However, 30% of this population seems to be refractory to the drug treatment. These patients are not seizure-free and frequently they show impaired cognitive functions. Unfortunately, as a side effect, some AEDs could contribute to such impairment. The major problem associated with conducting studies on epilepsy-related cognitive function is the lack of easy, rapid, specific and sensitive in vivo testing models. However, by using a number of different techniques and parameters in the zebrafish, we can incorporate the unique feature of specific disorder to study the molecular and behavior basis of this disease. In the view of current literature, the goal of the study was to develop a zebrafish model of epilepsy induced cognitive dysfunction. In this study, the effect of AEDs on locomotor activity and seizure-like behavior was tested against the pentylenetetrazole (PTZ) induced seizures in zebrafish and epilepsy associated cognitive dysfunction was determined using T-maze test followed by neurotransmitter estimation and gene expression analysis. It was observed that all the AEDs significantly reversed PTZ induced seizure in zebrafish, but had a negative impact on cognitive functions of zebrafish. AEDs were found to modulate neurotransmitter levels, especially GABA, glutamate, and acetylcholine and gene expression in the drug treated zebrafish brains. Therefore, combination of behavioral, neurochemical and genenetic information, makes this model a useful tool for future research and discovery of newer and safer AEDs.
    Matched MeSH terms: Neurotransmitter Agents
  2. Understanding the Pathophysiology of Premature Ejaculation: Bridging the Link between Pharmacological and Psychological Interventions
    Yusof F, Sidi H, Das S, Midin M, Kumar J, Hatta MH
    Curr Drug Targets, 2018;19(8):856-864.
    PMID: 27993112 DOI: 10.2174/1389450117666161215161108
    Premature ejaculation (PE) is one of the commonest male sexual dysfunctions. It is characterized by ejaculation which occurs before or soon after vaginal penetration, which causes significant psychological distress to the individual, and his partner. The exact cause of PE is still unknown but several mechanisms are proposed, and these involve complex interactions of neurophysiological, psychosocial, and cognitive factors. We discuss the role of serotonin, nitric oxide, phosphodiesterase enzymes and other neurotransmitters. Treatment of PE tends to co-occur with other sexual difficulties, especially erectile dysfunction (ED). Treatment with selective serotonin reuptake inhibitors (SSRIs) and Dapoxitene are also discussed in detail. The treatment strategy requires a comprehensive holistic approach incorporating both combination of psychopharmacological agent and cognitive-behavioral therapy (CBT). The present review highlights the integration of the hypothalamic-neural and reverberating emotional circuit and discusses the etiology and treatment for patients with PE.
    Matched MeSH terms: Neurotransmitter Agents/metabolism
  3. The neuromodulatory role of dopamine in improved reaction time by acute cardiovascular exercise
    Ando S, Fujimoto T, Sudo M, Watanuki S, Hiraoka K, Takeda K, et al.
    J Physiol, 2024 Feb;602(3):461-484.
    PMID: 38165254 DOI: 10.1113/JP285173
    Acute cardiovascular physical exercise improves cognitive performance, as evidenced by a reduction in reaction time (RT). However, the mechanistic understanding of how this occurs is elusive and has not been rigorously investigated in humans. Here, using positron emission tomography (PET) with [11 C]raclopride, in a multi-experiment study we investigated whether acute exercise releases endogenous dopamine (DA) in the brain. We hypothesized that acute exercise augments the brain DA system, and that RT improvement is correlated with this endogenous DA release. The PET study (Experiment 1: n = 16) demonstrated that acute physical exercise released endogenous DA, and that endogenous DA release was correlated with improvements in RT of the Go/No-Go task. Thereafter, using two electrical muscle stimulation (EMS) studies (Experiments 2 and 3: n = 18 and 22 respectively), we investigated what triggers RT improvement. The EMS studies indicated that EMS with moderate arm cranking improved RT, but RT was not improved following EMS alone or EMS combined with no load arm cranking. The novel mechanistic findings from these experiments are: (1) endogenous DA appears to be an important neuromodulator for RT improvement and (2) RT is only altered when exercise is associated with central signals from higher brain centres. Our findings explain how humans rapidly alter their behaviour using neuromodulatory systems and have significant implications for promotion of cognitive health. KEY POINTS: Acute cardiovascular exercise improves cognitive performance, as evidenced by a reduction in reaction time (RT). However, the mechanistic understanding of how this occurs is elusive and has not been rigorously investigated in humans. Using the neurochemical specificity of [11 C]raclopride positron emission tomography, we demonstrated that acute supine cycling released endogenous dopamine (DA), and that this release was correlated with improved RT. Additional electrical muscle stimulation studies demonstrated that peripherally driven muscle contractions (i.e. exercise) were insufficient to improve RT. The current study suggests that endogenous DA is an important neuromodulator for RT improvement, and that RT is only altered when exercise is associated with central signals from higher brain centres.
    Matched MeSH terms: Neurotransmitter Agents
  4. The debate over neurotransmitter interaction in aspartame usage
    Choudhary AK, Lee YY
    J Clin Neurosci, 2018 Oct;56:7-15.
    PMID: 30318075 DOI: 10.1016/j.jocn.2018.06.043
    Aspartame (NutraSweet®, Equal®) is a widely used artificial sweetener, has been reported to be accountable for neurological and behavioural disturbances in people. Upon ingestion, aspartame is hydrolyzed in gut and provides its metabolite; such as essential amino acid phenylalanine (Phy) (50%), aspartic acid (40%), and methanol (10%). Altered brain neurochemical compositions [such as dopamine (DA), norepinephrine (NE), and serotonin (5-HT)] have long been a concern and being involved in observed neurophysiological symptom (such as headaches, memory loss, mood changes, as well as depression) in aspartame consumers. Aspartames might act as chemical stressor through increasing plasma cortisol level. Aspartame consumption similarly altered gut microbiota. Taken together all this factors, we reviewed to search for convincing evidence, in what manner aspartame metabolites, stress hormones (cortisol), and gut dysbiosisis involved in altering brain neurochemical composition. We concluded that aspartame metabolite; mainly Phy and its interaction with neurotransmitter and aspartic acid by acting as excitatory neurotransmitter causes this pattern of impairments. Along with elevated cortisol and gut dysbiosis via interactions with different biogenic amine may also have additional impact to modulate neuronal signaling lead to neurobiological impairments. Hence ongoing research is instantly needed to understand the specific roles of aspartame metabolite, elevated cortisol, and gut dysbiosis with emerging neurophysiological symptom in aspartame consumers to improve healthy life in its consumers.
    Matched MeSH terms: Neurotransmitter Agents/metabolism*
  5. The Bio-Psycho-Social Dimension in Women's Sexual Desire: 'Argumentum ad novitatem'
    Roslan NS, Jaafar NRN, Sidi H, Baharudin N, Kumar J, Das S, et al.
    Curr Drug Targets, 2019;20(2):146-157.
    PMID: 28641524 DOI: 10.2174/1389450118666170622090337
    Sexual desire includes complex motivation and drive. In the context of biological and cognitive- emotive state art of science, it is often a neglected field in medicine. In regard to the treatment, study on women's sexual function received less attention compared to the men's sexuality. In the past, this endeavor was relatively not well disseminated in the scientific community. Recently, there was a revolutionized surge of drug targets available to treat women with low sexual desire. It is timely to review the relevant biological approach, especially in the context of pharmacotherapy to understand this interesting clinical entity which was modulated by numerous interactive psychosocial inter-play and factors. The complex inter-play between numerous dimensional factors lends insights to understand the neural mechanism, i.e. the rewards centre pathway and its interaction with external psychosocialstimulus, e.g. relationship or other meaningful life events. The function of hormones, e.g. oxytocin or testosterone regulation was described. The role of neurotransmitters as reflected by the introduction of a molecule of flibenserin, a full agonist of the 5-HT1A and partial agonist of the D4 to treat premenopausal women with low sexual desire was deliberated. Based on this fundamental scientific core knowledge, we suggest an outline on know-how of introduction for sex therapy (i.e. "inner-self" and "outer-self") where the role of partner is narrated. Then, we also highlighted on the use of pharmacological agent as an adjunct scope of therapy, i.e. phosphodiasterase-5 (PDE-5) inhibitors and hormonal treatment in helping the patient with low sexual desire.
    Matched MeSH terms: Neurotransmitter Agents/pharmacology; Neurotransmitter Agents/therapeutic use
  6. Role of α7 nicotinic acetylcholine receptor subtype in neuroprotection: an overview
    Muthuraju, S., Abdullah, J.M.
    Orient Neuron Nexus, 2011;2(1):10-14.
    MyJurnal
    Neuronal cell death results from various circumstances such as hypoxia, ischemic and neurodegenerative diseases (NDs). In these events, the resulting modification of neurotransmitters, either excitatory or inhibitory, mediate much of the neuronal damage. However, this consequence depends upon their pre and post synaptic receptor activities which are the key mechanism for signal regulation. Among these, acetylcholine (ACh) is a well known neurotransmitter which is predominantly involved in neuroprotection as well as cognitive functions through its receptors activity, particularly the nicotinic subtypes. Several lines of evidence suggest that among these subtypes, a7 nicotinic acetylcholine receptor (a7nAChR) offers much promise for neuroprotective role in relation to the central nervous system (CNS) disorders like schizophrenia and Alzheimer's disease (AD). Several lines of evidence exist to show the potential mechanisms in which this nAChR subtype and its agonists such as nicotine, that trigger the a7nAChR-mediated suppression of neuronal cell death. This review focuses on the potential role of a7nAChR in neuroprotection by examining recent experimental data, both in vitro and in vivo, that argue for the neuroprotective role of a7nAChR in the CNS.
    Matched MeSH terms: Neurotransmitter Agents
  7. Role of ambrisentan (selective endothelin-A receptor antagonist) on cigarette smoke exposure induced cognitive impairment in Danio rerio
    Muthuraman A, Nafisa K, Sowmya MS, Arpitha BM, Choedon N, Sandy CD, et al.
    Life Sci, 2019 Mar 04.
    PMID: 30844374 DOI: 10.1016/j.lfs.2019.03.002
    BACKGROUND: Cigarette smoke is exogenous modifiable factors to changes the neurovascular complication. The chronic exposure of cigarette smoke enhances neurocognitive dysfunction.

    AIMS: The present study is focused on evaluating the role of ambrisentan (selective endothelin-A receptor antagonist) on cigarette smoke-induced cognitive impairment in Danio rerio.

    MAIN METHODS: The cognitive dysfunction was developed by cigarette smoke exposure (CSE; 10 min in 25 ml of CSE per day) for five days. The selective endothelin-A receptor antagonist i.e., ambrisentan (2.5 to 5 mg/kg; i.p. for five consecutive days) was used for testing of CSE induced cognitive dysfunction. In addition, treatment of reference drug i.e., donepezil (10 mg/kg; i.p. for five consecutive days) was used for this cognitive function study. The cognitive functions were assessed by light and dark chamber; color recognition; partition preference; horizontal compartment; and T-Maze tests. Further, the CSE induced biomarkers changes of the zebrafish brain samples were estimated.

    KEY FINDINGS: The treatment of ambrisentan showed a potential ameliorative effect against the CSE induced cognitive functions along with attenuation of biochemical changes. The results are comparable to donepezil-treated groups.

    SIGNIFICANCE: Therefore, ambrisentan can be considered for the attenuation of CSE induced impairment neurocognitive functions due to its reduction of free radical scavenging and neuroinflammatory actions as well as regulation of cholinergic neurotransmitter functions.

    Matched MeSH terms: Neurotransmitter Agents
  8. Revisiting the role of neurotransmitters in epilepsy: An updated review
    Akyuz E, Polat AK, Eroglu E, Kullu I, Angelopoulou E, Paudel YN
    Life Sci, 2021 Jan 15;265:118826.
    PMID: 33259863 DOI: 10.1016/j.lfs.2020.118826
    Epilepsy is a neurologicaldisorder characterized by persistent predisposition to recurrent seizurescaused by abnormal neuronal activity in the brain. Epileptic seizures maydevelop due to a relative imbalance of excitatory and inhibitory neurotransmitters. Expressional alterations of receptors and ion channelsactivated by neurotransmitters can lead to epilepsy pathogenesis.

    AIMS: In this updated comprehensive review, we discuss the emerging implication of mutations in neurotransmitter-mediated receptors and ion channels. We aim to provide critical findings of the current literature about the role of neurotransmitters in epilepsy.

    MATERIALS AND METHODS: A comprehensive literature review was conducted to identify and critically evaluate studies analyzing the possible relationship between epilepsy and neurotransmitters. The PubMed database was searched for related research articles.

    KEY FINDINGS: Glutamate and gamma-aminobutyric acid (GABA) are the main neurotransmitters playing a critical role in the pathophysiology of this balance, and irreversible neuronal damage may occur as a result of abnormal changes in these molecules. Acetylcholine (ACh), the main stimulant of the autonomic nervous system, mediates signal transmission through cholinergic and nicotinic receptors. Accumulating evidence indicates that dysfunction of nicotinic ACh receptors, which are widely expressed in hippocampal and cortical neurons, may be significantly implicated in the pathogenesis of epilepsy. The dopamine-norepinephrine-epinephrine cycle activates hormonal and neuronal pathways; serotonin, norepinephrine, histamine, and melatonin can act as both hormones and neurotransmitters. Recent reports have demonstrated that nitric oxide mediates cognitive and memory-related functions via stimulating neuronal transmission.

    SIGNIFICANCE: The elucidation of the role of the main mediators and receptors in epilepsy is crucial for developing new diagnostic and therapeutic approaches.

    Matched MeSH terms: Neurotransmitter Agents/metabolism*
  9. Fulltext Review on Cross Talk between Neurotransmitters and Neuroinflammation in Striatum and Cerebellum in the Mediation of Motor Behaviour
    Abg Abd Wahab DY, Gau CH, Zakaria R, Muthu Karuppan MK, A-Rahbi BS, Abdullah Z, et al.
    Biomed Res Int, 2019;2019:1767203.
    PMID: 31815123 DOI: 10.1155/2019/1767203
    Neurological diseases particularly Alzheimer's disease (AD), Parkinson's disease (PD), stroke, and epilepsy are on the rise all around the world causing morbidity and mortality globally with a common symptom of gradual loss or impairment of motor behaviour. Striatum, which is a component of the basal ganglia, is involved in facilitating voluntary movement while the cerebellum is involved in the maintenance of balance and coordination of voluntary movements. Dopamine, serotonin, gamma-aminobutyric acid (GABA), and glutamate, to name a few, interact in regulating the excitation and inhibition of motor neurons. In another hand, interestingly, the motor loss associated with neurological diseases is possibly resulted from neuroinflammation induced by the neuroimmune system. Toll-like receptors (TLRs) are present in the central nervous system (CNS), specifically and primarily expressed in microglia and are also found on neurons and astrocytes, functioning mainly in the regulation of proinflammatory cytokine production. TLRs are always found to be associated or involved in the induction of neuroinflammation in neurodegenerative diseases. Activation of toll-like receptor 4 (TLR4) through TLR4 agonist, lipopolysaccharide (LPS), stimulation initiate a signaling cascade whereby the TLR4-LPS interaction has been found to result in physiological and behavioural changes including retardation of motor activity in the mouse model. TLR4 inhibitor TAK-242 was reflected in the reduction of the spinal cord pathology along with the motor improvement in ALS mouse. There is cross talk with neuroinflammation and neurochemicals. For example, TLR4 activation by LPS is noted to release proinflammatory cytokines, IL-1β, from microglia that subsequently suppresses GABA receptor activities at the postsynaptic site and reduces GABA synthesis at the presynaptic site. Glial glutamate transporter activities are also found to be suppressed, showing the association between TLR4 activation and the related neurotransmitters and corresponding receptors and transporters in the event of neuroinflammation. This review is helpful to understand the connection between neurotransmitter and neuroinflammation in striatum- and cerebellum-mediated motor behaviour.
    Matched MeSH terms: Neurotransmitter Agents/pharmacology*
  10. Probiotic consumption relieved human stress and anxiety symptoms possibly via modulating the neuroactive potential of the gut microbiota
    Ma T, Jin H, Kwok LY, Sun Z, Liong MT, Zhang H
    Neurobiol Stress, 2021 May;14:100294.
    PMID: 33511258 DOI: 10.1016/j.ynstr.2021.100294
    Stress has been shown to disturb the balance of human intestinal microbiota and subsequently causes mental health problems like anxiety and depression. Our previous study showed that ingesting the probiotic strain, Lactobacillus (L.) plantarum P-8, for 12 weeks could alleviate stress and anxiety of stressed adults. The current study was a follow-up work aiming to investigate the functional role of the gut metagenomes in the observed beneficial effects. The fecal metagenomes of the probiotic (n = 43) and placebo (n = 36) receivers were analyzed in depth. The gut microbiomes of the placebo group at weeks 0 and 12 showed a significantly greater Aitchison distance (P 
    Matched MeSH terms: Neurotransmitter Agents
  11. Fulltext Prediction of clinical symptoms of Schizophrenia based on COMT Methylation marker
    Nour El Huda Abd Rahim, Mohd Nabil Fikri Rahim, Norsidah Ku Zaifah, Hanisah Mohd Noor, Kartini Abdullah, Norlelawati A. Talib
    International Medical Journal Malaysia, 2017;16(11):19-19.
    MyJurnal
    The dopamine hypothesis of schizophrenia is based on the fact that hyperdopaminergic
    state is involved in causing psychosis and antipsychotic drugs block the
    dopamine receptor. COMT regulates the homeostatic levels of neurotransmitter
    dopamine in the synapses and plays a role in the neurocognitive function. The
    dysregulation of dopamine in the prefrontal cortex influences the cognitive function and
    the severity of the psychotic symptoms in schizophrenia. During epigenetic event,
    methylated COMT gene may cause reduction in its expression and contribute to the
    clinical presentation of schizophrenia. Therefore, the aim of this study was to assess the
    feasibility of using COMT DNA methylation for the prediction of specific psychotic
    presentation of schizophrenia. (Copied from article).
    Matched MeSH terms: Neurotransmitter Agents
  12. Fulltext Pilocarpine Induced Behavioral and Biochemical Alterations in Chronic Seizure-Like Condition in Adult Zebrafish
    Paudel YN, Kumari Y, Abidin SAZ, Othman I, Shaikh MF
    Int J Mol Sci, 2020 Apr 03;21(7).
    PMID: 32260203 DOI: 10.3390/ijms21072492
    Epilepsy is a devastating neurological condition exhibited by repeated spontaneous and unpredictable seizures afflicting around 70 million people globally. The basic pathophysiology of epileptic seizures is still elusive, reflecting an extensive need for further research. Developing a novel animal model is crucial in understanding disease mechanisms as well as in assessing the therapeutic target. Most of the pre-clinical epilepsy research has been focused on rodents. Nevertheless, zebrafish disease models are relevant to human disease pathophysiology hence are gaining increased attention nowadays. The current study for the very first time developed a pilocarpine-induced chronic seizure-like condition in adult zebrafish and investigated the modulation in several neuroinflammatory genes and neurotransmitters after pilocarpine exposures. Seizure score analysis suggests that compared to a single dose, repeated dose pilocarpine produces chronic seizure-like effects maintaining an average seizure score of above 2 each day for a minimum of 10 days. Compared to the single dose pilocarpine treated group, there was increased mRNA expression of HMGB1, TLR4, TNF-α, IL-1, BDNF, CREB-1, and NPY; whereas decreased expression of NF-κB was upon the repeated dose of pilocarpine administration. In addition, the epileptic group demonstrates modulation in neurotransmitters levels such as GABA, Glutamate, and Acetylcholine. Moreover, proteomic profiling of the zebrafish brain from the normal and epileptic groups from LCMS/MS quantification detected 77 and 13 proteins in the normal and epileptic group respectively. Summing up, the current investigation depicted that chemically induced seizures in zebrafish demonstrated behavioral and molecular alterations similar to classical rodent seizure models suggesting the usability of adult zebrafish as a robust model to investigate epileptic seizures.
    Matched MeSH terms: Neurotransmitter Agents/metabolism
  13. Pharmacological approaches for Alzheimer's disease: neurotransmitter as drug targets
    Prakash A, Kalra J, Mani V, Ramasamy K, Majeed AB
    Expert Rev Neurother, 2015 Jan;15(1):53-71.
    PMID: 25495260 DOI: 10.1586/14737175.2015.988709
    Alzheimer's disease (AD) is the most common CNS disorder occurring worldwide. There is neither proven effective prevention for AD nor a cure for patients with this disorder. Hence, there is an urgent need to develop safer and more efficacious drugs to help combat the tremendous increase in disease progression. The present review is an attempt at discussing the treatment strategies and drugs under clinical trials governing the modulation of neurotransmitter. Therefore, looking at neurotransmitter abnormalities, there is an urge for developing the pharmacological approaches aimed at correcting those abnormalities and dysfunctioning. In addition, this review also discusses the drugs that are in Phase III trials for the treatment of AD. Despite advances in treatment strategies aimed at correcting neurotransmitter abnormalities, there exists a need for the development of drug therapies focusing on the attempts to remove the pathogenomic protein deposits, thus combating the disease progression.
    Matched MeSH terms: Neurotransmitter Agents/metabolism*
  14. Fulltext Orthosiphon stamineus Proteins Alleviate Pentylenetetrazol-Induced Seizures in Zebrafish
    Chung YS, Choo BKM, Ahmed PK, Othman I, Shaikh MF
    Biomedicines, 2020 Jul 02;8(7).
    PMID: 32630817 DOI: 10.3390/biomedicines8070191
    The anticonvulsive potential of proteins extracted from Orthosiphon stamineus leaves (OSLP) has never been elucidated in zebrafish (Danio rerio). This study thus aims to elucidate the anticonvulsive potential of OSLP in pentylenetetrazol (PTZ)-induced seizure model. Physical changes (seizure score and seizure onset time, behavior, locomotor) and neurotransmitter analysis were elucidated to assess the pharmacological activity. The protective mechanism of OSLP on brain was also studied using mass spectrometry-based label-free proteomic quantification (LFQ) and bioinformatics. OSLP was found to be safe up to 800 µg/kg and pre-treatment with OSLP (800 µg/kg, i.p., 30 min) decreased the frequency of convulsive activities (lower seizure score and prolonged seizure onset time), improved locomotor behaviors (reduced erratic swimming movements and bottom-dwelling habit), and lowered the excitatory neurotransmitter (glutamate). Pre-treatment with OSLP increased protein Complexin 2 (Cplx 2) expression in the zebrafish brain. Cplx2 is an important regulator in the trans-SNARE complex which is required during the vesicle priming phase in the calcium-dependent synaptic vesicle exocytosis. Findings in this study collectively suggests that OSLP could be regulating the release of neurotransmitters via calcium-dependent synaptic vesicle exocytosis mediated by the "Synaptic Vesicle Cycle" pathway. OSLP's anticonvulsive actions could be acting differently from diazepam (DZP) and with that, it might not produce the similar cognitive insults such as DZP.
    Matched MeSH terms: Neurotransmitter Agents
  15. Neurotoxicity in Sri Lankan Russell's Viper (Daboia russelii) Envenoming is Primarily due to U1-viperitoxin-Dr1a, a Pre-Synaptic Neurotoxin
    Silva A, Kuruppu S, Othman I, Goode RJ, Hodgson WC, Isbister GK
    Neurotox Res, 2017 01;31(1):11-19.
    PMID: 27401825 DOI: 10.1007/s12640-016-9650-4
    Russell's vipers are snakes of major medical importance in Asia. Russell's viper (Daboia russelii) envenoming in Sri Lanka and South India leads to a unique, mild neuromuscular paralysis, not seen in other parts of the world where the snake is found. This study aimed to identify and pharmacologically characterise the major neurotoxic components of Sri Lankan Russell's viper venom. Venom was fractionated using size exclusion chromatography and reverse-phase high-performance liquid chromatography (RP-HPLC). In vitro neurotoxicities of the venoms, fractions and isolated toxins were measured using chick biventer and rat hemidiaphragm preparations. A phospholipase A2 (PLA2) toxin, U1-viperitoxin-Dr1a (13.6 kDa), which constitutes 19.2 % of the crude venom, was isolated and purified using HPLC. U1-viperitoxin-Dr1a produced concentration-dependent in vitro neurotoxicity abolishing indirect twitches in the chick biventer nerve-muscle preparation, with a t 90 of 55 ± 7 min only at 1 μM. The toxin did not abolish responses to acetylcholine and carbachol indicating pre-synaptic neurotoxicity. Venom, in the absence of U1-viperitoxin-Dr1a, did not induce in vitro neurotoxicity. Indian polyvalent antivenom, at the recommended concentration, only partially prevented the neurotoxic effects of U1-viperitoxin-Dr1a. Liquid chromatography mass spectrometry analysis confirmed that U1-viperitoxin-Dr1a was the basic S-type PLA2 toxin previously identified from this venom (NCBI-GI: 298351762; SwissProt: P86368). The present study demonstrates that neurotoxicity following Sri Lankan Russell's viper envenoming is primarily due to the pre-synaptic neurotoxin U1-viperitoxin-Dr1a. Mild neurotoxicity observed in severely envenomed Sri Lankan Russell's viper bites is most likely due to the low potency of U1-viperitoxin-Dr1a, despite its high relative abundance in the venom.
    Matched MeSH terms: Neurotransmitter Agents/pharmacology
  16. Neuroprotective potential of cinnamon and its metabolites in Parkinson's disease: Mechanistic insights, limitations, and novel therapeutic opportunities
    Angelopoulou E, Paudel YN, Piperi C, Mishra A
    J Biochem Mol Toxicol, 2021 Jan 24.
    PMID: 33491302 DOI: 10.1002/jbt.22720
    Parkinson's disease (PD) is the most common neurodegenerative movement disorder with obscure etiology and no disease-modifying therapy to date. Hence, novel, safe, and low cost-effective approaches employing medicinal plants are currently receiving increased attention. A growing body of evidence has revealed that cinnamon, being widely used as a spice of unique flavor and aroma, may exert neuroprotective effects in several neurodegenerative diseases, including PD. In vitro evidence has indicated that the essential oils of Cinnamomum species, mainly cinnamaldehyde and sodium benzoate may protect against oxidative stress-induced cell death, reactive oxygen species generation, and autophagy dysregulation, thus acting in a potentially neuroprotective manner. In vivo evidence has demonstrated that oral administration of cinnamon powder and sodium benzoate may protect against dopaminergic cell death, striatal neurotransmitter dysregulation, and motor deficits in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine mouse models of PD. The underlying mechanisms of its action include autophagy regulation, antioxidant effects, upregulation of Parkin, DJ-1, glial cell line-derived neurotrophic factor, as well as modulation of the TLR/NF-κB pathway and inhibition of the excessive proinflammatory responses. In addition, in vitro and in vivo studies have shown that cinnamon extracts may affect the oligomerization process and aggregation of α-synuclein. Herein, we discuss recent evidence on the novel therapeutic opportunities of this phytochemical against PD, indicating additional mechanistic aspects that should be explored, and potential obstacles/limitations that need to be overcome, for its inclusion in experimental PD therapeutics.
    Matched MeSH terms: Neurotransmitter Agents
  17. Neurophysiological symptoms and aspartame: What is the connection?
    Choudhary AK, Lee YY
    Nutr Neurosci, 2018 Jun;21(5):306-316.
    PMID: 28198207 DOI: 10.1080/1028415X.2017.1288340
    Aspartame (α-aspartyl-l-phenylalanine-o-methyl ester), an artificial sweetener, has been linked to behavioral and cognitive problems. Possible neurophysiological symptoms include learning problems, headache, seizure, migraines, irritable moods, anxiety, depression, and insomnia. The consumption of aspartame, unlike dietary protein, can elevate the levels of phenylalanine and aspartic acid in the brain. These compounds can inhibit the synthesis and release of neurotransmitters, dopamine, norepinephrine, and serotonin, which are known regulators of neurophysiological activity. Aspartame acts as a chemical stressor by elevating plasma cortisol levels and causing the production of excess free radicals. High cortisol levels and excess free radicals may increase the brains vulnerability to oxidative stress which may have adverse effects on neurobehavioral health. We reviewed studies linking neurophysiological symptoms to aspartame usage and conclude that aspartame may be responsible for adverse neurobehavioral health outcomes. Aspartame consumption needs to be approached with caution due to the possible effects on neurobehavioral health. Whether aspartame and its metabolites are safe for general consumption is still debatable due to a lack of consistent data. More research evaluating the neurobehavioral effects of aspartame are required.
    Matched MeSH terms: Neurotransmitter Agents/antagonists & inhibitors; Neurotransmitter Agents/metabolism
  18. Fulltext Neuroleptic malignant syndrome masked by cerebral malaria
    Rajesh KM, Sinnathamby V, Sakthi AN
    BMJ Case Rep, 2013;2013.
    PMID: 23704432 DOI: 10.1136/bcr-2013-009061
    A 38-year-old man with an underlying psychiatric illness presented with altered sensorium and abnormal behaviour. He was febrile at 38°C and weak looking; otherwise no other abnormalities were detected. A blood film conducted for malarial parasite (BFMP) revealed Plasmodium falciparum; hence a diagnosis of cerebral malaria was made. He was treated with antimalarial drugs for 2 days prior to being transferred out to the ward following clinical improvement. He subsequently developed episodes of stupor and refusal of feeding. Following an evaluation by the psychiatrist, a diagnosis of catatonic schizophrenia was made and he was started on oral sulpiride and benhexol. Unfortunately, he developed high-grade fever at 40°C with muscle rigidity and fasciculation. The diagnosis of neuroleptic malignant syndrome (NMS) was clinched and the antipsychotics were discontinued. However he succumbed to NMS several days later due to multiorgan failure.
    Matched MeSH terms: Neurotransmitter Agents/adverse effects*; Neurotransmitter Agents/therapeutic use
  19. Fulltext Neurohormetic phytochemicals: An evolutionary-bioenergetic perspective
    Murugaiyah V, Mattson MP
    Neurochem Int, 2015 Oct;89:271-80.
    PMID: 25861940 DOI: 10.1016/j.neuint.2015.03.009
    The impact of dietary factors on brain health and vulnerability to disease is increasingly appreciated. The results of epidemiological studies, and intervention trials in animal models suggest that diets rich in phytochemicals can enhance neuroplasticity and resistance to neurodegeneration. Here we describe how interactions of plants and animals during their co-evolution, and resulting reciprocal adaptations, have shaped the remarkable characteristics of phytochemicals and their effects on the physiology of animal cells in general, and neurons in particular. Survival advantages were conferred upon plants capable of producing noxious bitter-tasting chemicals, and on animals able to tolerate the phytochemicals and consume the plants as an energy source. The remarkably diverse array of phytochemicals present in modern fruits, vegetables spices, tea and coffee may have arisen, in part, from the acquisition of adaptive cellular stress responses and detoxification enzymes in animals that enabled them to consume plants containing potentially toxic chemicals. Interestingly, some of the same adaptive stress response mechanisms that protect neurons against noxious phytochemicals are also activated by dietary energy restriction and vigorous physical exertion, two environmental challenges that shaped brain evolution. In this perspective article, we describe some of the signaling pathways relevant to cellular energy metabolism that are modulated by 'neurohormetic phytochemicals' (potentially toxic chemicals produced by plants that have beneficial effects on animals when consumed in moderate amounts). We highlight the cellular bioenergetics-related sirtuin, adenosine monophosphate activated protein kinase (AMPK), mammalian target of rapamycin (mTOR) and insulin-like growth factor 1 (IGF-1) pathways. The inclusion of dietary neurohormetic phytochemicals in an overall program for brain health that also includes exercise and energy restriction may find applications in the prevention and treatment of a range of neurological disorders.
    Matched MeSH terms: Neurotransmitter Agents/administration & dosage; Neurotransmitter Agents/metabolism*
  20. Melatonin as an Antiepileptic Molecule: Therapeutic Implications via Neuroprotective and Inflammatory Mechanisms
    Akyuz E, Kullu I, Arulsamy A, Shaikh MF
    ACS Chem Neurosci, 2021 04 21;12(8):1281-1292.
    PMID: 33813829 DOI: 10.1021/acschemneuro.1c00083
    Epilepsy is a result of unprovoked, uncontrollable, and repetitive outburst of abnormal and excessive electrical discharges, known as seizures, in the neurons. Epilepsy is a devastating neurological condition that affects 70 million people globally. Unfortunately, only two-thirds of epilepsy patients respond to antiepileptic drugs while others become drug resistant and may be more prone to epilepsy comorbidities such as SUDEP. Oxidative stress, mitochondrial dysfunction, imbalance in the excitatory and inhibitory neurotransmitters, and neuroinflammation are some of the common pathologies of neurological disorders and epilepsy. Studies suggests that melatonin, a pineal hormone that governs sleep-wake cycles, may be neuroprotective against neurological disorders and thus may be translated as an antiepileptic as well. Melatonin has been shown to be an antioxidant, antiexcitotoxic, and anti-inflammatory hormone/molecule in neurodegenerative diseases, which may contribute to its antiepileptic and neuroprotective properties in epilepsy as well. In addition, melatonin has evidently been shown to play a regulatory role in the cardiorespiratory system and sleep-wake cycles, which may have positive implications toward epilepsy associated comorbidities, such as SUDEP. However, studies investigating the changes in melatonin release due to epilepsy and melatonin's antiepileptic role have been inconclusive and scarce, respectively. Thus, this comprehensive review aims to summarize and elucidate the potential role of melatonin in the pathogenesis of epilepsy and its comorbidities, in hopes to develop new diagnostic and therapeutic approaches that will improve the lives of epileptic patients, particularly those who are drug resistant.
    Matched MeSH terms: Neurotransmitter Agents
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