Neuritogenesis in cerebellar granule cells in vitro: a role for protein kinase C.
We have used short-term (8 h) cultures of week-old rat cerebellar granule cells to examine the effects on neuritogenesis of activation and down-regulation of protein kinase C by phorbol esters. We have previously demonstrated that endogenously released glutamate promoted neurite outgrowth in the same system acting via N-methyl-D-aspartate receptors. Low levels (0.1-1 nM) of the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) evoked increases in the number of granule cells which extended neurites; higher levels (10-250 nM) which caused a down-regulation of total protein kinase C, inhibited outgrowth in a dose-dependent manner. N-Methyl-D-aspartate by itself also stimulated process outgrowth but could not reverse the inhibition evoked by either TPA or the protein kinase C inhibitor sphingosine. Stimulation of protein kinase C with 0.1 nM TPA resulted in a general increase in the incorporation of 32P-labelled inorganic orthophosphate into granule cell polypeptides. The results indicate that the activation of protein kinase C is involved in neuritogenesis in granule cells and are consistent with the idea that N-methyl-D-aspartate receptor activation may exert its effect on neuritogenesis through protein kinase C.
Physiological Laboratory, University of Liverpool, U.K.
M A
MA
Cambray-Deakin
J
J
Adu
R D
RD
Burgoyne
D000470:Alkaloids / Q000494:pharmacology; D000818:Animals; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology; D003712:Dendrites / Q000187:drug effects / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D016202:N-Methylaspartate; D011493:Protein Kinase C / Q000378:metabolism / Q000502:physiology*; D051381:Rats; D013110:Sphingosine / Q000494:pharmacology; D019311:Staurosporine; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*
D000470:Alkaloids; D004791:Enzyme Inhibitors; D001224:Aspartic Acid; D016202:N-Methylaspartate; D011493:Protein Kinase C; D019311:Staurosporine; D013110:Sphingosine; D013755:Tetradecanoylphorbol Acetate