N-methyl-D-aspartate receptor-mediated spontaneous activity in cerebellar granule cells in culture.
An outside-out configuration of the patch-clamp method was used to study the properties of spontaneous and glutamate-evoked single channel activity in cerebellar granule cells in culture. Both spontaneous occurring events and glutamate-evoked single channel currents had similar conductances (17.7, 36.5; 17.3, 35.8 pS) and mean open times (0.7, 7.1; 0.6, 7.8 ms). In magnesium free solution, the spontaneous channels were blocked by the NMDA-receptor antagonist APV (0.1 mM) and by the NMDA-channel blocker MK-80 (0.1 mM). The spontaneous activity disappeared at negative holding potentials when the bathing solution contained magnesium (5 mM). Maximum conductance of spontaneous channels increased with days in culture (DIC) from 9 pS at 1 DIC to 59 pS at 10 DIC. These experiments suggest that endogenous transmitter activates NMDA-receptors in cerebellar granule cells in culture.
Scuola Internazionale Superiore di Studi Avanzati, SISSA, Trieste, Italy.
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G
Kilić
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O
Moran
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Cherubini
D015763:2-Amino-5-phosphonovalerate / Q000494:pharmacology; D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D015220:Calcium Channels / Q000187:drug effects; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology / Q000502:physiology*; D003035:Cobalt / Q000494:pharmacology; D016291:Dizocilpine Maleate / Q000494:pharmacology; D005971:Glutamates / Q000494:pharmacology; D018698:Glutamic Acid; D007736:Kynurenic Acid / Q000494:pharmacology; D016202:N-Methylaspartate / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D016194:Receptors, N-Methyl-D-Aspartate / Q000187:drug effects / Q000502:physiology*; D013779:Tetrodotoxin / Q000494:pharmacology
D015220:Calcium Channels; D005971:Glutamates; D016194:Receptors, N-Methyl-D-Aspartate; D003035:Cobalt; D018698:Glutamic Acid; D013779:Tetrodotoxin; D016202:N-Methylaspartate; D016291:Dizocilpine Maleate; D015763:2-Amino-5-phosphonovalerate; D007736:Kynurenic Acid