sq-23377 and Teratocarcinoma

We have investigated the possible role of second messengers on inositol homeostasis in NT2-N cells, human central nervous system neurons obtained by terminal differentiation of teratocarcinoma precursors. Uptake of inositol into NT2-N neurons was inhibited approximately 10% by protein kinase C (PKC) activation but was unaffected by either the presence of cyclic nucleotide analogs or changes in the intracellular concentration of Ca2+. Efflux of inositol from NT2-N neurons was enhanced in hypotonic buffer but virtually eliminated by inclusion of the Cl- channel blocker 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid, a result which indicates the involvement of a volume-sensitive organic osmolyte-anion channel. Volume-sensitive inositol efflux was stimulated approximately 30% following activation of PKC or elevation of the cytosolic Ca2+ concentration but was unaffected by protein kinase A activation. These results suggest that whereas inositol uptake into NT2-N neurons is relatively refractory to regulation, volume-sensitive inositol efflux may be significantly affected by intracellular signaling events.

Topics: 4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; Biological Transport; Calcium; Cell Differentiation; Cyclic GMP; Enzyme Activation; Humans; Hypotonic Solutions; Inositol; Ionomycin; Lithium; Neurons; Oxotremorine; Protein Kinase C; Second Messenger Systems; Signal Transduction; Teratocarcinoma; Tetradecanoylphorbol Acetate; Tritium; Tumor Cells, Cultured