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Modulation of N-methyl-d-aspartate receptor-mediated increases in cytosolic calcium in cultured rat cerebellar granule cells
| Content Provider | Semantic Scholar |
|---|---|
| Author | Parks, Thomas N. Artman, Linda D. Alasti, N. Nemeth, Edward F. |
| Copyright Year | 1991 |
| Abstract | The concentration of intracellular free Ca2+ ([Ca2+]i) was measured in rat cerebellar granule cells using the fluorescent indicator fura-2. Culturing the cells as monolayers on plastic squares which could be placed into cuvettes allowed measurements of [Ca2+]i to be performed on large and homogeneous populations of CNS neurons. Granule cells so cultured maintained low levels of [Ca2+]i (around 90 nM) which increased promptly upon the addition of various excitatory amino acids including N-methyl-D-aspartate (NMDA). Increases in [Ca2+]i elicited by NMDA were inhibited by Mg2+ (1 mM) and often potentiated by glycine (1 microM). The addition of TTX or strychnine (5 microM each) did not alter responses to NMDA or NMDA plus glycine. Cytosolic Ca2+ responses to NMDA/glycine were dependent on the presence of extracellular Ca2+ and were unaffected by concentrations of nifedipine or verapamil that blocked increases in [Ca2+]i elicited by K+ depolarization. Responses elicited by NMDA/glycine were inhibited competitively by 2-amino-5-phosphonovalerate or 3-((+-)-2-carboxypiperazin-4-yl)-propyl-1- phosphonic acid and non-competitively by MK-801 or Mg2+. HA-966 and 7-chlorokynurenate inhibited responses to NMDA alone and blocked competitively the potentiating effects of glycine. The results demonstrate NMDA-mediated increases in [Ca2+]i in cerebellar granule cells that arise solely from influx of extracellular Ca2+ through dihydropyridine-insensitive channels. The strict dependence of the NMDA-evoked response on extracellular Ca2+ provides little evidence for a coupling of NMDA receptors to inositol phosphate metabolism and mobilization of intracellular Ca2+. The effect of various agents on NMDA/glycine-induced increases in [Ca2+]i parallels their effects on ligand binding to or current flow through the NMDA receptor-channel complex. The measurement of cytosolic Ca2+ in this preparation of neuronal cells thus appears especially well suited for assessing, on a functional level, the regulation of NMDA receptors in the CNS. |
| Starting Page | 13 |
| Ending Page | 22 |
| Page Count | 10 |
| File Format | PDF HTM / HTML |
| DOI | 10.1016/0006-8993(91)90653-D |
| Alternate Webpage(s) | https://api.elsevier.com/content/article/pii/000689939190653D |
| Alternate Webpage(s) | https://www.sciencedirect.com/science/article/pii/000689939190653D?dgcid=api_sd_search-api-endpoint |
| PubMed reference number | 1833031 |
| Alternate Webpage(s) | https://doi.org/10.1016/0006-8993%2891%2990653-D |
| Journal | Medline |
| Volume Number | 552 |
| Journal | Brain Research |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
