Developmental changes in the inhibitory actions of ethanol on glutamate-induced translocation of protein kinase C in cerebellar granule neurons.
The effects of increasing concentrations of ethanol (25-200 mM) on the enhancement of [3H]phorbol-12,13-dibutyrate ([3H]PDBu) binding produced by different glutamate receptor agonists, indicative of a translocation of the intracellular enzyme protein kinase C (PKC), were studied in rat cerebellar granule cells at 2, 4, 8, and 12 days in vitro (DIV). Glutamate-produced stimulation of [3H]PDBu binding was inhibited by 50 mM ethanol at 2 DIV, whereas higher ethanol concentrations (> 100 mM) were needed to reduce the increase of [3H]PDBu binding in cells grown for 4, 8, and 12 DIV. Ethanol significantly inhibited NMDA-stimulated [3H]PDBu binding in a concentration-dependent fashion in cells maintained in culture for 4 and 8 days, respectively, with a slightly less pronounced inhibition by ethanol (50 mM) seen in cells kept for 2 and 12 DIV. Application of higher ethanol concentrations (> 100 mM), inhibited the NMDA-induced stimulation in all cell preparations. Following kainic acid-induced enhancement of [3H]PDBu binding, ethanol (100 mM) reduced the binding only in cells maintained for 2 DIV. Even higher ethanol concentrations (200 mM) inhibited the effects of kainic acid only in cells maintained for 2 and 4 DIV, respectively. Our data suggest that various subclasses of glutamate receptors display a developmentally determined differential sensitivity to ethanol at least in cerebellar granule cells in vitro.
Barrios
M
M
Department of Clinical Neuroscience, Karolinska Hospital, Stockholm, Sweden.
Liljequist
S
S
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002462:Cell Membrane / Q000201:enzymology; D002531:Cerebellum / Q000166:cytology / Q000201:enzymology* / Q000254:growth & development*; D003600:Cytosol / Q000201:enzymology; D000431:Ethanol / Q000494:pharmacology*; D018698:Glutamic Acid / Q000494:pharmacology*; D007608:Kainic Acid / Q000494:pharmacology; D016202:N-Methylaspartate / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects / Q000201:enzymology*; D015240:Phorbol 12,13-Dibutyrate / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014316:Tritium
D014316:Tritium; D015240:Phorbol 12,13-Dibutyrate; D000431:Ethanol; D018698:Glutamic Acid; D016202:N-Methylaspartate; D011493:Protein Kinase C; D007608:Kainic Acid