Regulation of N-methyl-d-aspartate receptor expression and N-methyl-d-aspartate-induced cellular response during chronic hypoxia in differentiated rat PC12 cells
| Autor: | D.E Millhorn, S Kobayashi |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
medicine.medical_specialty
endocrine system diseases Cell Survival medicine.drug_class Receptor expression Protein subunit Antigens Differentiation Myelomonocytic Biology PC12 Cells Receptors N-Methyl-D-Aspartate Internal medicine Nerve Growth Factor medicine Animals RNA Messenger Patch clamp Hypoxia Receptor General Neuroscience nutritional and metabolic diseases Cell Differentiation Receptor antagonist Rats Nerve growth factor Endocrinology Cell culture Chronic Disease NMDA receptor hormones hormone substitutes and hormone antagonists Transcription Factors |
| Zdroj: | Neuroscience. 101:1153-1162 |
| ISSN: | 0306-4522 |
| Popis: | The purpose of the present study was to examine the effect of chronic hypoxia on N -methyl- d -aspartate-mediated cellular responses in differentiated PC12 cells. PC12 cells were differentiated by treatment with nerve growth factor. Patch-clamp analysis in differentiated PC12 cells showed that extracellularly applied N -methyl- d -aspartate induced an inward current that was abolished by the presence of the N -methyl- d -aspartate receptor antagonist MK-801. Results from Ca 2+ imaging experiments showed that N -methyl- d -aspartate induced an elevation in intracellular free Ca 2+ which was also abolished by MK-801. We also examined the effect of hypoxia on the N -methyl- d -aspartate-induced current in nerve growth factor-treated cells. We found that the N -methyl- d -aspartate-induced inward current and the N -methyl- d -aspartate-induced elevation in intracellular free Ca 2+ were markedly attenuated by chronic hypoxia. We next examined the possibility that the reduced N -methyl- d -aspartate responsiveness was due to down-regulation of N -methyl- d -aspartate receptor levels. Northern blot and immunoblot analyses showed that both messenger RNA and protein levels for N -methyl- d -aspartate receptor subunit 1 were markedly decreased during hypoxia. However, the messenger RNA for N -methyl- d -aspartate receptor subunit 2C was increased, whereas the protein level for subunit 2C did not change. Our results indicate that differentiated PC12 cells express functional N -methyl- d -aspartate receptors and that chronic exposure to hypoxia attenuates the N -methyl- d -aspartate-induced Ca 2+ accumulation in these cells via down-regulation of N -methyl- d -aspartate receptor subunit 1. This mechanism may play an important role in protecting PC12 cells against hypoxic stress. |
| Databáze: | OpenAIRE |
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