Differential mechanisms of glutamate-stimulated perturbations in the kinetics of c-fos mRNA induction are associated with maturation of cerebellar granule cells in primary culture.
In further exploring proposals for the measurement of early gene (c-fos mRNA) levels as a predictive index for in vitro excitotoxicity, this study, using immature (2 days in vitro) cultures of mouse cerebellar granule cells as an experimental model system, was undertaken to determine the effect of glutamate (Glu) i) in stimulating increases in intracellular free-calcium ([Ca2+]), ii) on cell viability and iii) on induction of steady-state c-fos mRNA levels. In parallel experiments the action of agents (viz. 55 mM KCl and the calcium ionophore, A23187) that mediate Ca2+ entry into cells via different routes was also evaluated. Glu was unable to induce excitotoxicity in granule cells at this stage of development in culture, but did stimulate a concentration-dependent and marked increase in [Ca2+], levels while also mediating a dramatic concentration-dependent perturbation in the kinetics of c-fos mRNA induction that appeared to arise solely from NMDA receptor-mediated Ca2+ influx. The results are presented in comparison to the actions of KCI and A23187 and considered in relation to earlier studies undertaken using mature (7 days in vitro) cultures of cerebellar granule cells.
Griffiths
Roger
R
Neurochemistry Group, Centre for Biomolecular Sciences, University of St. Andrews, Fife, Scotland, United Kingdom. rg3@st-andrews.ac.uk
Grieve
Angus
A
Ritchie
Lyndsay
L
Scott
Mary
M
Meredith
Clive
C
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002470:Cell Survival; D002478:Cells, Cultured; D016922:Cellular Senescence / Q000502:physiology; D002531:Cerebellum / Q000166:cytology / Q000502:physiology*; D018698:Glutamic Acid / Q000494:pharmacology*; D007425:Intracellular Membranes / Q000378:metabolism; D007700:Kinetics; D051379:Mice; D008815:Mice, Inbred Strains; D009474:Neurons / Q000502:physiology*; D009994:Osmolar Concentration; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism*; D013997:Time Factors
D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; D018698:Glutamic Acid; D002118:Calcium