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Hyperbaric pressure and increased susceptibility to glutamate toxicity in retinal ganglion cells in vitro.

Aihara M, Chen YN, Uchida S, Nakayama M, Araie M - Mol. Vis. (2014)

Bottom Line: The effects of N-Methyl-D-aspartic acid (NMDA) and 2-amino-3-(5-methyl-3-oxo-1,2- oxazol-4-yl)propanoic acid (AMPA)/kainate receptor antagonists, MK-801, and 6,7-dinitroquinoxaline-2,3-dione (DNQX), on cell survival were assessed.MK-801 and DNQX significantly reduced glutamate-induced RGC death, and DNQX was more effective than MK-801.In a rat RGC culture, hyperbaric pressure alone did not induce RGC death but increased RGC susceptibility to glutamate toxicity, which may be of relevance to ocular diseases with pressure-induced RGC death.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, University of Tokyo School of Medicine, Tokyo, Japan.

ABSTRACT

Purpose: To investigate the effect of hyperbaric pressure on purified retinal ganglion cells (RGCs) and the additive effect of hyperbaric pressure on glutamate-induced RGC death.

Methods: An RGC primary culture from 8-day-old Wistar rats was prepared and cultured in a hyperbaric chamber. The RGC survival rate under various pressure conditions and with 5 or 25 µM of glutamate stimulation was determined and compared with that of RGCs under isobaric conditions. First, RGCs were cultured at atmospheric pressure (0 mmHg) and under hyperbaric pressure (+30 and +90 mmHg, with pressure fluctuations varying from 0 to +30 or +60 mmHg). Next, RGCs were cultured at +15, +30, and +90 mmHg with the addition of 5 or 25 µM of glutamate. The effects of N-Methyl-D-aspartic acid (NMDA) and 2-amino-3-(5-methyl-3-oxo-1,2- oxazol-4-yl)propanoic acid (AMPA)/kainate receptor antagonists, MK-801, and 6,7-dinitroquinoxaline-2,3-dione (DNQX), on cell survival were assessed. Additionally, types of cell death and the induction of Bcl-2-associated X protein (BAX) leading to apoptosis were studied under hyperbaric pressure conditions and/or with 5 µM of glutamate.

Results: RGC death was not induced under increasing or fluctuating pressure conditions. RGC death was induced by 25 µM of glutamate and increased as pressure increased. RGC death was not induced by 5 µM of glutamate but was induced by and increased with increasing pressure. MK-801 and DNQX significantly reduced glutamate-induced RGC death, and DNQX was more effective than MK-801. Under hyperbaric pressure conditions, the addition of 5 µM of glutamate resulted in the induction of apoptosis and BAX, which did not occur under hyperbaric pressure conditions or with the addition of glutamate alone.

Conclusion: In a rat RGC culture, hyperbaric pressure alone did not induce RGC death but increased RGC susceptibility to glutamate toxicity, which may be of relevance to ocular diseases with pressure-induced RGC death.

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Related in: MedlinePlus

The effects of glutamate receptor antagonists, MK801 and DNQX, on glutamate toxicity at 0 (isobaric; A), +15 (B), +30 (C), and +90 mmHg (D) pressure. Both MK801 and DNQX partially inhibited glutamate-induced cell death, and its protective effect was higher in DNQX than in MK801. Data indicates mean±SD, *; p<0.05, **; p<0.01 from Tukey’s test, n=8.
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f3: The effects of glutamate receptor antagonists, MK801 and DNQX, on glutamate toxicity at 0 (isobaric; A), +15 (B), +30 (C), and +90 mmHg (D) pressure. Both MK801 and DNQX partially inhibited glutamate-induced cell death, and its protective effect was higher in DNQX than in MK801. Data indicates mean±SD, *; p<0.05, **; p<0.01 from Tukey’s test, n=8.

Mentions: With 5 µM of glutamate, the survival rates of the 0 mmHg, 0 mmHg with MK801, and 0 mmHg with DNQX groups were similar to that of the control culture without glutamate (100.4±3.9% and 99.1±2.9% versus 100.3±4.0%). With 25 µM of glutamate, the survival rates of the 0 mmHg, 0 mmHg with MK801, and 0 mmHg with DNQX groups were 69.1±8.9%, 88.2±7.9%, and 98.7±3.9%, respectively (p<0.05 and p<0.01, respectively; Dunnett’s test; Figure 3A).


Hyperbaric pressure and increased susceptibility to glutamate toxicity in retinal ganglion cells in vitro.

Aihara M, Chen YN, Uchida S, Nakayama M, Araie M - Mol. Vis. (2014)

The effects of glutamate receptor antagonists, MK801 and DNQX, on glutamate toxicity at 0 (isobaric; A), +15 (B), +30 (C), and +90 mmHg (D) pressure. Both MK801 and DNQX partially inhibited glutamate-induced cell death, and its protective effect was higher in DNQX than in MK801. Data indicates mean±SD, *; p<0.05, **; p<0.01 from Tukey’s test, n=8.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4016804&req=5

f3: The effects of glutamate receptor antagonists, MK801 and DNQX, on glutamate toxicity at 0 (isobaric; A), +15 (B), +30 (C), and +90 mmHg (D) pressure. Both MK801 and DNQX partially inhibited glutamate-induced cell death, and its protective effect was higher in DNQX than in MK801. Data indicates mean±SD, *; p<0.05, **; p<0.01 from Tukey’s test, n=8.
Mentions: With 5 µM of glutamate, the survival rates of the 0 mmHg, 0 mmHg with MK801, and 0 mmHg with DNQX groups were similar to that of the control culture without glutamate (100.4±3.9% and 99.1±2.9% versus 100.3±4.0%). With 25 µM of glutamate, the survival rates of the 0 mmHg, 0 mmHg with MK801, and 0 mmHg with DNQX groups were 69.1±8.9%, 88.2±7.9%, and 98.7±3.9%, respectively (p<0.05 and p<0.01, respectively; Dunnett’s test; Figure 3A).

Bottom Line: The effects of N-Methyl-D-aspartic acid (NMDA) and 2-amino-3-(5-methyl-3-oxo-1,2- oxazol-4-yl)propanoic acid (AMPA)/kainate receptor antagonists, MK-801, and 6,7-dinitroquinoxaline-2,3-dione (DNQX), on cell survival were assessed.MK-801 and DNQX significantly reduced glutamate-induced RGC death, and DNQX was more effective than MK-801.In a rat RGC culture, hyperbaric pressure alone did not induce RGC death but increased RGC susceptibility to glutamate toxicity, which may be of relevance to ocular diseases with pressure-induced RGC death.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, University of Tokyo School of Medicine, Tokyo, Japan.

ABSTRACT

Purpose: To investigate the effect of hyperbaric pressure on purified retinal ganglion cells (RGCs) and the additive effect of hyperbaric pressure on glutamate-induced RGC death.

Methods: An RGC primary culture from 8-day-old Wistar rats was prepared and cultured in a hyperbaric chamber. The RGC survival rate under various pressure conditions and with 5 or 25 µM of glutamate stimulation was determined and compared with that of RGCs under isobaric conditions. First, RGCs were cultured at atmospheric pressure (0 mmHg) and under hyperbaric pressure (+30 and +90 mmHg, with pressure fluctuations varying from 0 to +30 or +60 mmHg). Next, RGCs were cultured at +15, +30, and +90 mmHg with the addition of 5 or 25 µM of glutamate. The effects of N-Methyl-D-aspartic acid (NMDA) and 2-amino-3-(5-methyl-3-oxo-1,2- oxazol-4-yl)propanoic acid (AMPA)/kainate receptor antagonists, MK-801, and 6,7-dinitroquinoxaline-2,3-dione (DNQX), on cell survival were assessed. Additionally, types of cell death and the induction of Bcl-2-associated X protein (BAX) leading to apoptosis were studied under hyperbaric pressure conditions and/or with 5 µM of glutamate.

Results: RGC death was not induced under increasing or fluctuating pressure conditions. RGC death was induced by 25 µM of glutamate and increased as pressure increased. RGC death was not induced by 5 µM of glutamate but was induced by and increased with increasing pressure. MK-801 and DNQX significantly reduced glutamate-induced RGC death, and DNQX was more effective than MK-801. Under hyperbaric pressure conditions, the addition of 5 µM of glutamate resulted in the induction of apoptosis and BAX, which did not occur under hyperbaric pressure conditions or with the addition of glutamate alone.

Conclusion: In a rat RGC culture, hyperbaric pressure alone did not induce RGC death but increased RGC susceptibility to glutamate toxicity, which may be of relevance to ocular diseases with pressure-induced RGC death.

Show MeSH
Related in: MedlinePlus