Platelet-activating factor increases glutamine synthetase activity in early and late passage C-6 glioma cells

S. Kentroti, R. Baker, Kendall H Lee, C. Bruce, A. Vernadakis

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

Previous studies from this laboratory have shown that C-6 rat glioma cells (2B clone) exhibit specific phenotypic characteristics depending on passage in culture and that these populations respond differentially to addition of various exogenous compounds to the medium. Early passage (<25) C-6 glial cells express low glutamine synthetase activity (a marker for astrocytes) and with increasing cell passage (>70) C-6 glial cells express more astrocytic properties with respect to both glutamine synthetase (GS) and morphology. In this study, cells from both early (glioblastic) and late (astrocytic) passage were examined for their response to the phospholipid, platelet-activating factor (PAF). We found that PAF increased GS activity in early passage (glioblastic) cells and more importantly it increased GS activity in late passage cells, already committed to the astrocytic phenotype. Furthermore, cells from both passages failed to respond to addition of lyso-PAF, the non-biologically active analog of PAF, to the medium. By following the uptake of 3H-PAF into cells, we observed that >90% of the phospholipid was taken into the cells within the first hour of incubation. We compared the PAF effects with that of dibutyryl cyclic AMP (dBcAMP) and RO20-1724, a phosphodiesterase inhibitor. Cells from the early passage responded to both dBcAMP and RO20-1724 treatments with a significant increase in GS activity whereas cells from the late passage showed no significant change, confirming earlier reports from this laboratory. These findings indicate that the response of C-6 glioma cells to PAF (at least in the late passage) is not mediated via cyclic AMP. We suggest that in early passage cells PAF promotes expression of the astrocytic phenotype and in late passage cells PAF mediates a gliosis-type response.

Original languageEnglish (US)
Pages (from-to)497-506
Number of pages10
JournalJournal of Neuroscience Research
Volume28
Issue number4
StatePublished - 1991
Externally publishedYes

Fingerprint

Glutamate-Ammonia Ligase
Platelet Activating Factor
Glioma
Bucladesine
Phospholipids
Phenotype
Gliosis
Phosphodiesterase Inhibitors
Neuroglia
Cyclic AMP
Clone Cells

Keywords

  • astrocytic phenotype
  • C-6 glioma cells
  • phenotypic expression
  • platelet-activating factor

ASJC Scopus subject areas

  • Neuroscience(all)

Cite this

Platelet-activating factor increases glutamine synthetase activity in early and late passage C-6 glioma cells. / Kentroti, S.; Baker, R.; Lee, Kendall H; Bruce, C.; Vernadakis, A.

In: Journal of Neuroscience Research, Vol. 28, No. 4, 1991, p. 497-506.

Research output: Contribution to journalArticle

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