Role of transporters and ion channels in neuronal injury under hypoxia

The aims of the current study were to 1) examine the effects of hypoxia and acidosis on cultured cortical neurons and 2) explore the role of transporters and ion channels in hypoxic injury. Cell injury was measured in cultured neurons or hippocampal slices following hypoxia (1% O2) or acidosis (medium pH 6.8) treatment. Inhibitors of transporters and ion channels were employed to investigate their roles in hypoxic injury. Our results showed that 1) neuronal damage was apparent at 5–7 days of hypoxia exposure, i.e., 36–41% of total lactate dehydrogenase was released to medium and 2) acidosis alone did not lead to significant injury compared with nonacidic, normoxic controls. Pharmacological studies revealed 1) no significant difference in neuronal injury between controls (no inhibitor) and inhibition of Na+-K+-ATP pump, voltage-gated Na+ channel, ATP-sensitive K+ channel, or reverse mode of Na+/Ca2+ exchanger under hypoxia; however, 2) inhibition of NBCs with 500 μM DIDS did not cause hypoxic death in either cultured cortical neurons or hippocampal slices; 3) in contrast, inhibition of Na+/H+ exchanger isoform 1 (NHE1) with either 10 μM HOE-642 or 2 μM T-162559 resulted in dramatic hypoxic injury (+95% for HOE-642 and +100% for T-162559 relative to normoxic control, P < 0.001) on treatment day 3, when no death occurred for hypoxic controls (no inhibitor). No further damage was observed by NHE1 inhibition on treatment day 5. We conclude that inhibition of NHE1 accelerates hypoxia-induced neuronal damage. In contrast, DIDS rescues neuronal death under hypoxia. Hence, DIDS-sensitive mechanism may be a potential therapeutic target.

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Neuroprotective role of δ-opioid receptors in cortical neurons

AJP Cell Physiology ◽

10.1152/ajpcell.00226.2001 ◽

2002 ◽

Vol 282 (6) ◽

pp. C1225-C1234 ◽

Cited By ~ 114

Author(s):

Junhui Zhang ◽

Geoffrey Thomas Gibney ◽

Peng Zhao ◽

Ying Xia

Keyword(s):

Opioid Receptor ◽

Cortical Neurons ◽

Cell Injury ◽

Prolonged Exposure ◽

Neuronal Injury ◽

Receptor Activation ◽

Hypoxic Exposure ◽

Hypoxic Injury ◽

Hypoxic Conditions ◽

Lactate Dehydrogenase Release

We recently demonstrated that δ-opioid receptor (DOR) activation protects cortical neurons against glutamate-induced injury. Because glutamate is a mediator of hypoxic injury in neurons, we hypothesized that DOR is involved in neuroprotection during O2 deprivation and that its activation/inhibition may alter neuronal susceptibility to hypoxic stress. In this work, we tested the effect of opioid receptor activation and inhibition on cultured cortical neurons in hypoxia (1% O2). Cell injury was assessed by lactate dehydrogenase release, morphology-based quantification, and live/dead staining. Our results show that 1) immature neurons ( days 4 and 6) were not significantly injured by hypoxia until 72 h of exposure, whereas day 8 neurons were injured after only 24-h hypoxia; 2) DOR inhibition (naltrindole) caused neuronal injury in both day 4 and day 8 normoxic cultures and further augmented hypoxic injury in these neurons; 3) DOR activation ([d-Ala2,d-Leu5]enkephalin) reduced neuronal injury in day 8 cultures after 24 h of normoxic or hypoxic exposure and attenuated naltrindole-induced injury with prolonged exposure; and 4) μ- or κ-opioid receptor inhibition (β-funaltrexamine or nor-binaltorphimine) had little effect on neurons in either normoxic or hypoxic conditions. Collectively, these data suggest that DOR plays a crucial role in neuroprotection in normoxic and hypoxic environments.

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The dual role of KCNQ/M channels upon OGD or OGD/R insults in cultured cortical neurons of mice: Timing is crucial in targeting M‐channels against ischemic injur ies

Journal of Cellular Physiology ◽

10.1002/jcp.27889 ◽

2018 ◽

Vol 234 (8) ◽

pp. 12714-12726

Author(s):

Yu Diao ◽

Weijie Yan ◽

Wei Sun ◽

Yanlin Luo ◽

Junfa Li ◽

...

Keyword(s):

Cortical Neurons ◽

Dual Role ◽

Cultured Cortical Neurons ◽

M Channels

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Glucose Deprivation Neuronal Injury in vitro is Modified by Withdrawal of Extracellular Glutamine

Journal of Cerebral Blood Flow & Metabolism ◽

10.1038/jcbfm.1990.62 ◽

1990 ◽

Vol 10 (3) ◽

pp. 337-342 ◽

Cited By ~ 18

Author(s):

Hannelore Monyer ◽

Dennis W. Choi

Keyword(s):

Cortical Neurons ◽

Excitatory Amino Acids ◽

Neuronal Loss ◽

Nmda Antagonist ◽

Neuronal Injury ◽

Glucose Deprivation ◽

Glutamine Concentration ◽

Energy Substrate ◽

Cultured Cortical Neurons

Cultured cortical neurons deprived of glucose in a defined solution containing 2 m M glutamine became acutely swollen and went on to degenerate over the next day; this neuronal loss could be substantially attenuated by an N-methyl-D-aspartate (NMDA) antagonist. Removal of extracellular glutamine produced two effects: an increase in overall neuronal injury and a decrease in the protective effect of an NMDA antagonist. Both effects of glutamine removal were glutamine concentration dependent (EC50 for both ∼300 μ M) and not reversed by substitution of equimolar concentrations of alanine or arginine. These observations suggest that glucose deprivation neuronal injury may be tonically regulated by the presence of extracellular glutamine. We speculate that glutamine may reduce overall injury by serving as an energy substrate in the absence of glucose, but may increase NMDA receptor-mediated injury by serving as a precursor for transmitter excitatory amino acids.

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Combination of mild hypothermia with neuroprotectants has greater neuroprotective effects during oxygen-glucose deprivation and reoxygenation-mediated neuronal injury

Scientific Reports ◽

10.1038/srep07091 ◽

2014 ◽

Vol 4 (1) ◽

Cited By ~ 27

Author(s):

Xiao-Ya Gao ◽

Jian-Ou Huang ◽

Ya-Fang Hu ◽

Yong Gu ◽

Shu-Zhen Zhu ◽

...

Keyword(s):

Cortical Neurons ◽

Mild Hypothermia ◽

Neuronal Damage ◽

Combined Treatment ◽

Neuronal Injury ◽

Glucose Deprivation ◽

Oxygen Glucose Deprivation ◽

Single Treatment ◽

Neuroprotective Effects ◽

Apoptosis Pathway

Abstract Co-treatment of neuroprotective reagents may improve the therapeutic efficacy of hypothermia in protecting neurons during ischemic stroke. This study aimed to find promising drugs that enhance the neuroprotective effect of mild hypothermia (MH). 26 candidate drugs were selected based on different targets. Primary cultured cortical neurons were exposed to oxygen-glucose deprivation and reoxygenation (OGD/R) to induce neuronal damage, followed by either single treatment (a drug or MH) or a combination of a drug and MH. Results showed that, compared with single treatment, combination of MH with brain derived neurotrophic factor, glibenclamide, dizocilpine, human urinary kallidinogenase or neuroglobin displayed higher proportion of neuronal cell viability. The latter three drugs also caused less apoptosis rate in combined treatment. Furthermore, co-treatment of those three drugs and MH decreased the level of reactive oxygen species (ROS) and intracellular calcium accumulation, as well as stabilized mitochondrial membrane potential (MMP), indicating the combined neuroprotective effects are probably via inhibiting mitochondrial apoptosis pathway. Taken together, the study suggests that combined treatment with hypothermia and certain neuroprotective reagents provide a better protection against OGD/R-induced neuronal injury.

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Acid-sensing ion channels regulate spontaneous inhibitory activity in the hippocampus: possible implications for epilepsy

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2015.0431 ◽

2016 ◽

Vol 371 (1700) ◽

pp. 20150431 ◽

Cited By ~ 13

Author(s):

O. Ievglevskyi ◽

D. Isaev ◽

O. Netsyk ◽

A. Romanov ◽

M. Fedoriuk ◽

...

Keyword(s):

Ion Channels ◽

Hippocampal Neurons ◽

Hippocampal Slices ◽

Synaptic Activity ◽

Mammalian Brain ◽

Strong Increase ◽

Life And Death ◽

Acid Sensing Ion Channels

Acid-sensing ion channels (ASICs) play an important role in numerous functions in the central and peripheral nervous systems ranging from memory and emotions to pain. The data correspond to a recent notion that each neuron and many glial cells of the mammalian brain express at least one member of the ASIC family. However, the mechanisms underlying the involvement of ASICs in neuronal activity are poorly understood. However, there are two exceptions, namely, the straightforward role of ASICs in proton-based synaptic transmission in certain brain areas and the role of the Ca 2+ -permeable ASIC1a subtype in ischaemic cell death. Using a novel orthosteric ASIC antagonist, we have found that ASICs specifically control the frequency of spontaneous inhibitory synaptic activity in the hippocampus. Inhibition of ASICs leads to a strong increase in the frequency of spontaneous inhibitory postsynaptic currents. This effect is presynaptic because it is fully reproducible in single synaptic boutons attached to isolated hippocampal neurons. In concert with this observation, inhibition of the ASIC current diminishes epileptic discharges in a low Mg 2+ model of epilepsy in hippocampal slices and significantly reduces kainate-induced discharges in the hippocampus in vivo . Our results reveal a significant novel role for ASICs. This article is part of the themed issue ‘Evolution brings Ca 2+ and ATP together to control life and death’.

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Shp2 in Forebrain Neurons Regulates Synaptic Plasticity, Locomotion, and Memory Formation in Mice

Molecular and Cellular Biology ◽

10.1128/mcb.01339-14 ◽

2015 ◽

Vol 35 (9) ◽

pp. 1557-1572 ◽

Cited By ~ 20

Author(s):

Shinya Kusakari ◽

Fumihito Saitow ◽

Yukio Ago ◽

Koji Shibasaki ◽

Miho Sato-Hashimoto ◽

...

Keyword(s):

Synaptic Plasticity ◽

Cortical Neurons ◽

Tyrosine Phosphatase ◽

Hippocampal Slices ◽

Memory Formation ◽

Conditional Knockout ◽

Abnormal Behavior ◽

Erk Activation ◽

Cultured Cortical Neurons ◽

Forebrain Neurons

Shp2 (Src homology 2 domain-containing protein tyrosine phosphatase 2) regulates neural cell differentiation. It is also expressed in postmitotic neurons, however, and mutations of Shp2 are associated with clinical syndromes characterized by mental retardation. Here we show that conditional-knockout (cKO) mice lacking Shp2 specifically in postmitotic forebrain neurons manifest abnormal behavior, including hyperactivity. Novelty-induced expression of immediate-early genes and activation of extracellular-signal-regulated kinase (Erk) were attenuated in the cerebral cortex and hippocampus of Shp2 cKO mice, suggestive of reduced neuronal activity. In contrast, ablation of Shp2 enhanced high-K+-induced Erk activation in both cultured cortical neurons and synaptosomes, whereas it inhibited that induced by brain-derived growth factor in cultured neurons. Posttetanic potentiation and paired-pulse facilitation were attenuated and enhanced, respectively, in hippocampal slices from Shp2 cKO mice. The mutant mice also manifested transient impairment of memory formation in the Morris water maze. Our data suggest that Shp2 contributes to regulation of Erk activation and synaptic plasticity in postmitotic forebrain neurons and thereby controls locomotor activity and memory formation.

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Ca2+-dependent mechanisms of cell injury in cultured cortical neurons

Neuroscience ◽

10.1016/s0306-4522(98)00070-0 ◽

1998 ◽

Vol 86 (4) ◽

pp. 1133-1144 ◽

Cited By ~ 34

Author(s):

M.R Castillo ◽

J.R Babson

Keyword(s):

Cortical Neurons ◽

Cell Injury ◽

Cultured Cortical Neurons

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Role of Dysregulated Ion Channels in Sensory Neurons in Chronic Kidney Disease-Associated Pruritus

Medicines ◽

10.3390/medicines6040110 ◽

2019 ◽

Vol 6 (4) ◽

pp. 110 ◽

Cited By ~ 3

Author(s):

Akishi Momose ◽

Micihihiro Yabe ◽

Shigetoshi Chiba ◽

Kenjirou Kumakawa ◽

Yasuo Shiraiwa ◽

...

Keyword(s):

Chronic Kidney Disease ◽

Ion Channels ◽

Kidney Disease ◽

Peripheral Nerve ◽

Nerve Endings ◽

Generator Potential ◽

Arteriovenous Fistulas ◽

Significant Difference ◽

G Protein Coupled

Background: We investigated ion channels at the skin, including peripheral nerve endings, which serve as output machines and molecular integrators of many pruritic inputs mainly received by multiple G protein-coupled receptors (GPCRs). Methods: Based on the level of chronic kidney disease–associated pruritus (CKD-aP), subjects were divided into two groups: non-CKD-aP (no or slight pruritus; n = 12) and CKD-aP (mild, moderate, or severe pruritus; n = 11). Skin samples were obtained from the forearm or elbow during operations on arteriovenous fistulas. We measured ion channels expressed at the skin, including peripheral nerve endings by RT-PCR: Nav1.8, Kv1.4, Cav2.2, Cav3.2, BKCa, Anoctamin1, TRPV1, TRPA1, and ASIC. Results: Expression of Cav3.2, BKCa, and anoctamin1 was significantly elevated in patients with CKD-aP. On the other hand, expression of TRPV1 was significantly reduced in these patients. We observed no significant difference in the levels of Cav2.2 or ASIC between subjects with and without CKD-aP. TRPA1, Nav1.8, and Kv1.4 were not expressed. Conclusions: It was concluded that this greater difference in the expression of ion channels in the skin tissue including, specially cutaneous peripheral nerve endings in CKD patients with CKD-aP may increase generator potential related to itching.

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