Favorable Response to “Memantine” in a Child with GRIN2B Epileptic Encephalopathy

2021 ◽  
Author(s):  
Sathya Chidambaram ◽  
Ranjith Kumar Manokaran
Keyword(s):  
Nmda Receptor ◽  
Cognitive Processes ◽  
Neurodevelopmental Outcome ◽  
Nmda Receptor Antagonist ◽  
Genetic Mutation ◽  
Epileptic Encephalopathy ◽  
Gene Encoding ◽  
Epileptic Spasms ◽  
The Family

Abstract GRIN2B is a gene encoding GluN2B subunit under the family of N-methyl D-aspartate (NMDA) receptors, which is responsible for neurogenesis and cognitive processes. The role of NMDA receptor antagonists like memantine is being explored for therapies in drug-resistant epilepsies. Here, we present a case of a 20-month-old boy who presented with refractory epileptic spasms. Upon failure of multiple antiepileptic drugs, he was started on oral memantine. There was a significant reduction in average seizure episodes by ∼80%. The use of memantine along with antiepileptic drug polytherapy has proved to be beneficial in our case. Our experience with memantine and favorable outcome opens up the scope of more research into the use of NMDA receptor antagonist as a drug option for refractory epilepsies with proven genetic mutation and hence improves the overall neurodevelopmental outcome and survival chance.

Protective Effect of Ifenprodil Against Spreading Depression in the Mouse Entorhinal Cortex

2004 ◽  
Vol 92 (4) ◽  
pp. 2610-2614 ◽  
Author(s):  
Leonardo Coutinho Faria ◽  
Istvan Mody
Keyword(s):  
Nmda Receptor ◽  
Entorhinal Cortex ◽  
Spreading Depression ◽  
Ion Homeostasis ◽  
Brain Slices ◽  
Nmda Receptor Antagonist ◽  
Cerebrovascular Diseases ◽  
Nr2b Receptor Subunit ◽  
Nr2b Receptor

In the brain, spreading depression (SD) is characterized by a large extracellular DC shift, a massive failure of ion homeostasis and a transient cessation of neuronal function. Clinically, SD is believed to be involved in various neurological disorders including migraine and cerebrovascular diseases. The propagation of cortical SD requires the release of glutamate, and N-methyl-d-aspartate (NMDA) receptors play a crucial role in this process. Here, we have isolated the NMDA receptor-mediated component of extracellularly recorded field excitatory postsynaptic potentials (fEPSPs) in layers 2–3 of the entorhinal cortex of murine brain slices. In the absence of GABAA and AMPA receptor-mediated synaptic transmission, stimulation of layer 6 afferents every 15–90 s elicited spontaneous SD on average within 18.5 min after the start of the stimulation. In the presence of ifenprodil, an NR2B receptor subunit-selective NMDA receptor antagonist, the occurrence of SD was nearly abolished. Our results are consistent with an important role of NR2B subunits in triggering SD in the entorhinal cortex.

Role of AMPA/kainate receptors in transmission of the sympathetic baroreflex in rat CVLM

1997 ◽  
Vol 272 (3) ◽  
pp. R800-R812 ◽  
Author(s):  
T. Miyawaki ◽  
S. Suzuki ◽  
J. Minson ◽  
L. Arnolda ◽  
J. Chalmers ◽  
...  
Keyword(s):  
Nmda Receptor ◽  
Receptor Antagonist ◽  
Nmda Receptor Antagonist ◽  
Baroreceptor Reflex ◽  
Significant Inhibition ◽  
Kainate Receptors ◽  
Ventrolateral Medulla ◽  
Mk 801 ◽  
Aortic Nerve

We examined the role of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)/kainate receptors within the caudal ventrolateral medulla (CVLM) in mediating the sympathetic baroreceptor reflex in anesthetized and paralyzed rats. Bilateral microinjection into CVLM of either DL-2-amino-5-phosphonovaleric acid [APV; a selective N-methyl-D-aspartic acid (NMDA) receptor antagonist, 20 mM, 100 nl] or 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX; a selective AMPA/kainate receptor antagonist, 2 mM, 100 nl) alone failed to eliminate the aortic nerve stimulation-evoked hypotension and inhibition of splanchnic sympathetic nerve activity (SNA) or the cardiac-related rhythmicity of SNA. All components of the sympathetic-baroreceptor reflex were abolished when kynurenate (100 mM, 30 nl) or mixtures of APV and CNQX (10 and 1 mM, respectively, 100 or 30 nl) were injected into CVLM. Injection of APV or CNQX into CVLM reduced aortic nerve-evoked inhibitory responses of bulbospinal sympathoexcitatory neurons in rostral ventrolateral medulla (RVLM). The extent of this reduction was variable. Usually, significant inhibition was preserved. In seven RVLM neurons, intravenous injection of MK-801 (NMDA receptor antagonist, 2 mg/kg) failed to eliminate aortic nerve-evoked inhibitory responses. However, inhibitory responses were abolished when CNQX was injected into CVLM after intravenous MK-801. We conclude that both NMDA and AMPA/kainate receptors in CVLM transmit baroreceptor information.

Role of the medullary lateral tegmental field in reflex-mediated sympathoexcitation in cats

2004 ◽  
Vol 286 (3) ◽  
pp. R451-R464 ◽  
Author(s):  
Hakan S. Orer ◽  
Gerard L. Gebber ◽  
Shaun W. Phillips ◽  
Susan M. Barman
Keyword(s):  
Nmda Receptor ◽  
Nmda Receptors ◽  
Receptor Antagonist ◽  
Sympathetic Nerve Activity ◽  
Nmda Receptor Antagonist ◽  
Vagal Afferents ◽  
Reflex Pathways ◽  
Excitatory Responses ◽  
Stimulation Of

We tested the hypothesis that blockade of N-methyl-d-aspartate (NMDA) and non-NMDA receptors on medullary lateral tegmental field (LTF) neurons would reduce the sympathoexcitatory responses elicited by electrical stimulation of vagal, trigeminal, and sciatic afferents, posterior hypothalamus, and midbrain periaqueductal gray as well as by activation of arterial chemoreceptors with intravenous NaCN. Bilateral microinjection of a non-NMDA receptor antagonist into LTF of urethane-anesthetized cats significantly decreased vagal afferent-evoked excitatory responses in inferior cardiac and vertebral nerves to 29 ± 8 and 24 ± 6% of control ( n = 7), respectively. Likewise, blockade of non-NMDA receptors significantly reduced chemoreceptor reflex-induced increases in inferior cardiac (from 210 ± 22 to 129 ± 13% of control; n = 4) and vertebral nerves (from 253 ± 41 to 154 ± 20% of control; n = 7) and mean arterial pressure (from 39 ± 7 to 21 ± 5 mmHg; n = 8). Microinjection of muscimol, but not an NMDA receptor antagonist, caused similar attenuation of these excitatory responses. Sympathoexcitatory responses to the other stimuli were not attenuated by microinjection of a non-NMDA receptor antagonist or muscimol into LTF. In fact, excitatory responses elicited by stimulation of trigeminal, and in some cases sciatic, afferents were enhanced. These data reveal two new roles for the LTF in control of sympathetic nerve activity in cats. One, LTF neurons are involved in mediating sympathoexcitation elicited by activation of vagal afferents and arterial chemoreceptors, primarily via activation of non-NMDA receptors. Two, non-NMDA receptor-mediated activation of other LTF neurons tonically suppresses transmission in trigeminal-sympathetic and sciatic-sympathetic reflex pathways.

Nicotine-induced anxiogenic-like behaviours of rats in the elevated plus-maze: possible role of NMDA receptors of the central amygdala

2011 ◽  
Vol 26 (4) ◽  
pp. 555-563 ◽  
Author(s):  
Mohammad Reza Zarrindast ◽  
Arash Aghamohammadi-Sereshki ◽  
Ameneh Rezayof ◽  
Parvin Rostami
Keyword(s):  
Locomotor Activity ◽  
Nmda Receptor ◽  
Nmda Receptors ◽  
Elevated Plus Maze ◽  
Nmda Receptor Antagonist ◽  
Central Amygdala ◽  
Receptor System ◽  
Plus Maze ◽  
Male Wistar Rats

The objective of the present study was to investigate the possible role of the N-methyl-D-aspartate (NMDA) receptor system of the central amygdala (CeA) in the anxiogenic-like effect of nicotine. Male Wistar rats with cannulas aimed to the CeA were submitted to the elevated plus-maze (EPM). Intraperitoneal (i.p.) injections of nicotine (0.6 and 0.8 mg/kg) decreased percentage open arm time spent (%OAT) and percentage open arm entries (%OAE), but not locomotor activity, indicating an anxiogenic-like response. Bilateral intra-CeA microinjection of NMDA (0.005–0.1 μ g/rat) decreased %OAT, but not %OAE and locomotor activity. Moreover, intra-CeA microinjection of NMDA (0.05 μ g) with an ineffective dose of nicotine (0.4 mg/kg, i.p.) reduced %OAT and %OAE without effect on locomotor activity. On the other hand, intra-CeA microinjection of the NMDA receptor antagonist D-AP5 (0.05–0.5 μ g/rat) increased both %OAT and %OAE, showing an anxiolytic-like effect of the drug. Co-administration of the same doses of D-AP5 with nicotine (0.6 mg/kg, i.p.) increased %OAT and %OAE, but not locomotor activity. Intra-CeA microinjection of D-AP5 reversed the response induced by NMDA (0.1 μ g/rat) in the EPM. The results may support the possible involvement of glutamate transmission, through NMDA receptors of central amygdala in the anxiogenic-like effect of nicotine in the EPM task.

scholarly journals NMDA Receptor Mediates the Anticonvulsant Effect of Hydroalcoholic Extract of Artemisia persica in PTZ-Induced Seizure in Mice

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Shakiba Nasiri-Boroujeni ◽  
Mohammad Rahimi-Madiseh ◽  
Zahra Lorigooini ◽  
Khadijeh Piroti ◽  
Mahmoud Rafieian-Koupaei ◽  
...  
Keyword(s):  
Nmda Receptor ◽  
Antioxidant Capacity ◽  
Nmda Receptor Antagonist ◽  
Seizure Threshold ◽  
Anticonvulsant Effect ◽  
Stress Effect ◽  
Hydroalcoholic Extract ◽  
Nmda Receptor Subunits ◽  
Antioxidative Stress

It is necessary to seek more effective sources to design new drug against epilepsy. This study aimed to evaluate the effect of hydroalcoholic extract of Artemisia persica on pentylenetetrazole- (PTZ-) induced seizure in male mice by investigating the possible role of the NMDA receptor and antioxidative stress effect. The phenolic profile of A. persica extract was determined by HPLC-DAD analysis. Mice were treated with normal saline or A. persica extract or pentobarbital or a subeffective dose of extract plus ketamine (NMDA receptor antagonist) and/or effective dose of extract plus NMDA. PTZ (90 mg/kg) was injected intravenously for induction of seizure. The seizure threshold was measured. Then mice were euthanized and the antioxidant capacity and the level of malondialdehyde (MDA) of the prefrontal cortex and serum were measured. The gene expression of NMDA receptor subunits (Nr2a and Nr2b) was determined by real-time PCR. Findings showed that A. persica extract increased the seizure threshold, increased antioxidant capacity, and decreased MDA levels in the serum and brain samples. A. persica extract reduced the expression of NMDA receptor subunits. The result showed that ketamine potentiated the effect of the subeffective dose of extract. HPLC analysis showed that quercetin had the highest flavonoid content and also caffeic acid had the highest content of the phenolic acids. A. persica extract probably via NMDA receptor exerts anticonvulsant properties.

Role of excitatory amino acids in mediating burst discharge of red nucleus neurons in the in vitro turtle brain stem-cerebellum

1991 ◽  
Vol 65 (3) ◽  
pp. 454-467 ◽  
Author(s):  
J. Keifer ◽  
J. C. Houk
Keyword(s):  
Spinal Cord ◽  
Amino Acid ◽  
Nmda Receptor ◽  
Excitatory Amino Acid ◽  
Red Nucleus ◽  
Nmda Receptor Antagonist ◽  
Excitatory Amino Acid Receptor ◽  
Bath Application

1. Bursts of discharge have been recorded in the red nucleus in several species and are thought to represent the expression of motor commands. A cerebellorubral circuit comprised of recurrent connections among the cerebellum, red nucleus, and reticular formation was postulated to function as a positive feedback loop that generates these motor commands and transmits them to the spinal cord via the rubrospinal pathway. We have used an in vitro preparation from the turtle that leaves the circuitry connecting the cerebellum, brain stem, and spinal cord intact to study the role of excitatory amino acid neurotransmitters and recurrent excitation in mediating the generation of burst discharges in the red nucleus. 2. Burst discharges were recorded extracellularly from single cells in the red nucleus in response to single pulse or brief train stimulation of the contralateral spinal cord or brief train stimuli applied to the ipsilateral cerebellar cortex. The firing characteristics and pharmacologic sensitivities of the bursts were independent of the type of stimulus used. The bursts had long durations ranging from 2 to 17 s and showed spike frequency adaptation. 3. Transection of the cerebellar peduncle, which eliminates inhibition impinging onto the cerebellorubral circuit, greatly enhanced the spontaneous activity and burst discharges recorded in the contralateral red nucleus. Furthermore, bath application of a solution containing elevated levels of calcium and magnesium blocked the expression of burst discharges even though synaptic activation of the neurons was not blocked. 4. The possibility that excitatory amino acid receptors mediate burst responses in the red nucleus was investigated in light of the antagonistic effects of elevated magnesium ions on bursting. Bath application of 100 microns DL-2-amino-5-phosphonovaleric acid (APV), a specific N-methyl-D-aspartate (NMDA) receptor antagonist; [10 microM 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX)], a specific non-NMDA receptor antagonist; or 100 microM, DL-2-amino-4-phosphonobutyric acid (AP4), an agonist of a fourth class of excitatory amino acid receptor, blocked burst activity in the red nucleus. With a multibarreled pipette for simultaneous ejection of drug and recording, iontophoresis of APV or CNQX into the red nucleus blocked bursting whereas AP4 failed to show a significant effect. These data suggest that red nucleus neurons have both NMDA and non-NMDA receptors. The site of action of the AP4-sensitive receptor appears to be elsewhere in the cerebellorubral circuit. 5. Iontophoretic application of excitatory amino acid receptor agonists NMDA and quisqualate (Q) induced excitation of red nucleus neurons.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Restoration of contractility in hyperhomocysteinemia by cardiac-specific deletion of NMDA-R1

2009 ◽  
Vol 296 (3) ◽  
pp. H887-H892 ◽  
Author(s):  
Karni S. Moshal ◽  
Munish Kumar ◽  
Neetu Tyagi ◽  
Paras K. Mishra ◽  
Naira Metreveli ◽  
...  
Keyword(s):  
Nmda Receptor ◽  
Detection System ◽  
Calcium Transient ◽  
Nmda Receptor Antagonist ◽  
No Production ◽  
Contraction And Relaxation ◽  
Myocyte Contractility ◽  
Metalloproteinase 9 ◽  
Specific Deletion

Homocysteine (HCY) activated mitochondrial matrix metalloproteinase-9 and led to cardiomyocyte dysfunction, in part, by inducing mitochondrial permeability (MPT). Treatment with MK-801 [ N-methyl-d-aspartate (NMDA) receptor antagonist] ameliorated the HCY-induced decrease in myocyte contractility. However, the role of cardiomyocyte NMDA-receptor 1 (R1) activation in hyperhomocysteinemia (HHCY) leading to myocyte dysfunction was not well understood. We tested the hypothesis that the cardiac-specific deletion of NMDA-R1 mitigated the HCY-induced decrease in myocyte contraction, in part, by decreasing nitric oxide (NO). Cardiomyocyte-specific knockout of NMDA-R1 was generated using cre/lox technology. NMDA-R1 expression was detected by Western blot and confocal microscopy. MPT was determined using a spectrophotometer. Myocyte contractility and calcium transients were studied using the IonOptix video-edge detection system and fura 2-AM loading. We observed that HHCY induced NO production by agonizing NMDA-R1. HHCY induced the MPT by agonizing NMDA-R1. HHCY caused a decrease in myocyte contractile performance, maximal rate of contraction and relaxation, and prolonged the time to 90% peak shortening and 90% relaxation by agonizing NMDA-R1. HHCY decreased contraction amplitude with the increase in calcium concentration. The recovery of calcium transient was prolonged in HHCY mouse myocyte by agonizing NMDA-R1. It was suggested that HHCY increased mitochondrial NO levels and induced MPT, leading to the decline in myocyte mechanical function by agonizing NMDA-R1.

Pharmacological approaches

2019 ◽  
pp. 85-94
Author(s):  
Navneet Kapur ◽  
Robert Goldney
Keyword(s):  
Nmda Receptor ◽  
Psychiatric Disorder ◽  
Antipsychotic Medication ◽  
Pharmacological Treatment ◽  
Nmda Receptor Antagonist ◽  
Research Interest ◽  
Mood Stabilizers ◽  
Short Acting ◽  
The Subject

This chapter discusses the role of pharmacological approaches to the treatment of people who present with suicidal thoughts or behaviours. Use of medication has been controversial, particularly for children. However, the balance of evidence suggests that if there is a psychiatric disorder for which there is an effective pharmacological treatment, then this treatment should be offered. Antidepressants, mood stabilizers (particularly lithium), and antipsychotic medication can reduce suicidality. Ketamine, a short-acting anaesthetic and NMDA receptor antagonist, is potentially useful and is the subject of much research interest for its possible role in treatment.

scholarly journals Evolution of Bacterial Global Modulators: Role of a Novel H-NS Paralogue in the EnteroaggregativeEscherichia coliStrain 042

mSystems ◽  
2018 ◽  
Vol 3 (3) ◽  
Author(s):  
A. Prieto ◽  
M. Bernabeu ◽  
S. Aznar ◽  
S. Ruiz-Cruz ◽  
A. Bravo ◽  
...  
Keyword(s):  
Protein A ◽  
Bacterial Cells ◽  
Gene Encoding ◽  
Specific Expression ◽  
Protein Targets ◽  
Global Regulators ◽  
E Coli ◽  
The Family ◽  
Regulatory Properties

ABSTRACTBacterial genomes sometimes contain genes that code for homologues of global regulators, the function of which is unclear. In members of the familyEnterobacteriaceae, cells express the global regulator H-NS and its paralogue StpA. InEscherichia coli, out of providing a molecular backup for H-NS, the role of StpA is poorly characterized. The enteroaggregativeE. colistrain 042 carries, in addition to thehnsandstpAgenes, a third gene encoding anhnsparalogue (hns2). We present in this paper information about its biological function. Transcriptomic analysis has shown that the H-NS2 protein targets a subset of the genes targeted by H-NS. Genes targeted by H-NS2 correspond mainly with horizontally transferred (HGT) genes and are also targeted by the Hha protein, a fine-tuner of H-NS activity. Compared with H-NS, H-NS2 expression levels are lower. In addition, H-NS2 expression exhibits specific features: it is sensitive to the growth temperature and to the nature of the culture medium. This novel H-NS paralogue is widespread within theEnterobacteriaceae.IMPORTANCEGlobal regulators such as H-NS play key relevant roles enabling bacterial cells to adapt to a changing environment. H-NS modulates both core and horizontally transferred (HGT) genes, but the mechanism by which H-NS can differentially regulate these genes remains to be elucidated. There are several instances of bacterial cells carrying genes that encode homologues of the global regulators. The question is what the roles of these proteins are. We noticed that the enteroaggregativeE. colistrain 042 carries a new hitherto uncharacterized copy of thehnsgene. We decided to investigate why this pathogenicE. colistrain requires an extra H-NS paralogue, termed H-NS2. In our work, we show that H-NS2 displays specific expression and regulatory properties. H-NS2 targets a subset of H-NS-specific genes and may help to differentially modulate core and HGT genes by the H-NS cellular pool.

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