Abstract
Growth conditions which promote the survival of cerebellar granule cells in culture, such as high K+ or N-methyl-D-aspartate (NMDA) treatment, also promote the functional expression of an NMDA-preferring subtype alone of the ionotropic glutamate receptors. The selective regulation of NMDA receptors detected electrophysiologically in individual cells, using the whole cell patch clamp technique, is characteristic of granule cells in general: NMDA-induced 45Ca2+ influx increased several-fold in cultures treated with either high K+ or NMDA. The increase in NMDA receptor activity was correlated with an increase in the expression of an NMDA receptor protein. Since the effect of these 'trophic' conditions is mediated through Ca2+, the induced increase in the density of NMDA receptors (which gate a Ca2+ conductance) provides a positive feedback for strengthening the trophic influences.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Calcium / metabolism
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Calcium Channels / drug effects
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Calcium Channels / metabolism
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Cell Survival / drug effects
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Cells, Cultured
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Cerebellar Cortex / cytology*
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Glutamates / pharmacology
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Glutamic Acid
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Glycine / pharmacology
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Ibotenic Acid / analogs & derivatives
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Ibotenic Acid / pharmacology
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Ion Channel Gating / drug effects
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Kainic Acid / pharmacology
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Magnesium / pharmacology
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N-Methylaspartate / pharmacology*
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Neurons / drug effects*
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Neurons / metabolism
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Potassium / pharmacology*
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Quisqualic Acid / pharmacology
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Rats
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Receptors, Glutamate
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Receptors, N-Methyl-D-Aspartate / biosynthesis*
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Receptors, Neurotransmitter / biosynthesis*
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Up-Regulation / drug effects
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alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid
Substances
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Calcium Channels
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Glutamates
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Receptors, Glutamate
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Receptors, N-Methyl-D-Aspartate
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Receptors, Neurotransmitter
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Ibotenic Acid
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Glutamic Acid
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N-Methylaspartate
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alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid
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Quisqualic Acid
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Magnesium
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Potassium
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Kainic Acid
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Calcium
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Glycine