Molecular mechanism of acute ammonia toxicity: role of NMDA receptors

2002 ◽  
Vol 41 (2-3) ◽  
pp. 95-102 ◽  
Author(s):  
Pilar Monfort ◽  
Elena Kosenko ◽  
Slaven Erceg ◽  
Juan-José Canales ◽  
Vicente Felipo
Keyword(s):  
Nmda Receptors ◽  
Molecular Mechanism ◽  
Ammonia Toxicity

Role of NMDA receptors in acute liver failure and ammonia toxicity: Therapeutical implications

2009 ◽  
Vol 55 (1-3) ◽  
pp. 113-118 ◽  
Author(s):  
Regina Rodrigo ◽  
Omar Cauli ◽  
Jordi Boix ◽  
Nisrin ElMlili ◽  
Ana Agusti ◽  
...  
Keyword(s):  
Liver Failure ◽  
Acute Liver Failure ◽  
Nmda Receptors ◽  
Ammonia Toxicity

Artificial RNA Editing with ADAR for Gene Therapy

2020 ◽  
Vol 20 (1) ◽  
pp. 44-54 ◽  
Author(s):  
Sonali Bhakta ◽  
Toshifumi Tsukahara
Keyword(s):  
Gene Therapy ◽  
Genetic Code ◽  
Molecular Mechanism ◽  
Rna Editing ◽  
Comparative Studies ◽  
Genetic Diseases ◽  
Adenosine Deaminases ◽  
Family Protein ◽  
Hydrolytic Deamination

Editing mutated genes is a potential way for the treatment of genetic diseases. G-to-A mutations are common in mammals and can be treated by adenosine-to-inosine (A-to-I) editing, a type of substitutional RNA editing. The molecular mechanism of A-to-I editing involves the hydrolytic deamination of adenosine to an inosine base; this reaction is mediated by RNA-specific deaminases, adenosine deaminases acting on RNA (ADARs), family protein. Here, we review recent findings regarding the application of ADARs to restoring the genetic code along with different approaches involved in the process of artificial RNA editing by ADAR. We have also addressed comparative studies of various isoforms of ADARs. Therefore, we will try to provide a detailed overview of the artificial RNA editing and the role of ADAR with a focus on the enzymatic site directed A-to-I editing.

Role of NMDA receptors in noise-induced tau hyperphosphorylation in rat hippocampus and prefrontal cortex

2014 ◽  
Vol 340 (1-2) ◽  
pp. 191-197 ◽  
Author(s):  
Kang Li ◽  
Hengchuan Jia ◽  
Xiaojun She ◽  
Bo Cui ◽  
Na Zhang ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Nmda Receptors ◽  
Rat Hippocampus ◽  
Tau Hyperphosphorylation

Evaluation of the role of N-methyl-D-aspartate (NMDA) receptors in insulin secreting beta-cells

2016 ◽  
Vol 771 ◽  
pp. 107-113 ◽  
Author(s):  
Steven Patterson ◽  
Nigel Irwin ◽  
Hong Guo-Parke ◽  
R. Charlotte Moffett ◽  
Siobhan M. Scullion ◽  
...  
Keyword(s):  
Nmda Receptors ◽  
Beta Cells

Role of adenosine in NMDA receptor modulation in the cerebral cortex of an anoxia-tolerant turtle (Chrysemys picta belli).

1995 ◽  
Vol 198 (7) ◽  
pp. 1621-1628 ◽  
Author(s):  
L T Buck ◽  
P E Bickler
Keyword(s):  
Cerebral Cortex ◽  
Nmda Receptor ◽  
Nmda Receptors ◽  
Control Level ◽  
Chrysemys Picta ◽  
Receptor Modulation ◽  
A1 Receptor ◽  
Excitatory Neurotransmission ◽  
Similar Decrease

Accumulation of the neuromodulator adenosine in the anoxia-tolerant turtle brain may play a key role in a protective decrease in excitatory neurotransmission during anoxia. Since excitatory neurotransmission is mediated largely by Ca2+ entry through N-methyl-D-aspartate (NMDA) receptors, we measured the effect of adenosine on NMDA-mediated Ca2+ transients in normoxic and anoxic turtle cerebrocortical sheets. Intracellular [Ca2+] was measured fluorometrically with the Ca2+-sensitive dye Fura-2. Baseline intracellular [Ca2+] and [ATP] were also measured to assess cortical sheet viability and potential toxic effects of NMDA. Baseline [Ca2+] did not change significantly under any condition, ranging from 109 +/- 22 to 187 +/- 26 nmoll-1. Throughout normoxic and 2h anoxic protocols, and after single and multiple NMDA exposures, [ATP] did not change significantly, ranging from 16.0 +/- 1.9 to 25.3 +/- 4.9 nmol ATP mg-1 protein. Adenosine caused a reduction in the normoxic NMDA-mediated increase in [Ca2+] from a control level of 287 +/- 35 to 103 +/- 22 nmoll-1 (64%). This effect is mediated by the A1 receptor since 8-phenyltheophylline (a specific A1 antagonist) effectively blocked the adenosine effect and N6-cyclopentyladenosine (a specific A1 agonist) elicited a similar decrease in the NMDA-mediated response. Cortical sheets exposed to anoxia alone exhibited a 52% decrease in the NMDA-mediated [Ca2+] rise, from 232 +/- 30 to 111 +/- 9 nmoll-1. The addition of adenosine had no further effect and 8-phenyltheophylline did not antagonize the observed decrease. Therefore, the observed down-regulation of NMDA receptor activity during anoxia must involve additional, as yet unknown, mechanisms.

Role of N-methyl-D-aspartate receptors in the pontine pneumotaxic mechanism in the cat

1994 ◽  
Vol 76 (3) ◽  
pp. 1138-1143 ◽  
Author(s):  
L. Ling ◽  
D. R. Karius ◽  
D. F. Speck
Keyword(s):  
Nmda Receptor ◽  
Nmda Receptors ◽  
Partial Recovery ◽  
Inspiratory Time ◽  
Systemic Injection ◽  
Lung Inflation ◽  
Mk 801 ◽  
Efferent Limb ◽  
Adult Cats

Systemic injection of MK-801, an N-methyl-D-aspartate (NMDA) receptor-associated channel blocker, induces an apneusis in vagotomized cats similar to that produced by pontine respiratory group (PRG) lesions, suggesting the possible involvement of NMDA receptors in the pontine pneumotaxic mechanism. Previous results from our laboratory indicate that the efferent limb of the pontine pneumotaxic mechanism is unlikely to require NMDA receptor-mediated neurotransmission. Therefore, the present study examined the potential involvement of PRG NMDA receptors in the pontine pneumotaxic mechanism. Experiments were conducted in decerebrate, paralyzed, and ventilated adult cats. The effects on inspiratory time (TI) of MK-801 microinjection into PRG were tested in 12 cats. Pressure microinjection of MK-801 (15 mM, 80–3,000 nl) significantly prolonged TI in all animals when lung inflation was withheld. TI progressively increased in most animals for > or = 30 min. After this period, partial recovery of the effect occurred in eight cats as TI shortened toward predrug levels. In three animals, microinjection of MK-801 induced a complete apneusis in the absence of lung inflation from which there was no detectable recovery. Microinjections into regions approximately 2 mm distant from PRG produced little or no effect. These results provide evidence that NMDA receptors located in the region of PRG play an important functional role in the control of the breathing cycle.

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