Depolarization and insulin-like growth factor-I (IGF-I) differentially regulate the mitotic cycle in cultured rat sympathetic neuroblasts.
Although neuroblast generation is highly reproducible temporospatially, the underlying regulation is undefined. Employing a fully defined sympathetic neuroblast culture system, we previously found that insulin growth factors regulated the mitotic cycle. We now report that depolarizing stimuli, including elevated K+ and veratridine, also increased the proportion of mitotic neuroblasts in vitro. Moreover, Na+ channel blockade prevented effects of depolarization, but not that of insulin-like growth factor I, suggesting that these influences stimulate mitosis by different membrane transduction mechanisms.
DiCicco-Bloom
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Department of Neurology, Cornell University Medical College, New York, NY 10021.
Black
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D000818:Animals; D002453:Cell Cycle / Q000187:drug effects; D002478:Cells, Cultured; D004622:Embryo, Mammalian; D005728:Ganglia, Sympathetic / Q000166:cytology* / Q000187:drug effects / Q000502:physiology; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D008938:Mitosis / Q000187:drug effects*; D011188:Potassium / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012964:Sodium / Q000502:physiology; D013002:Somatomedins / Q000494:pharmacology*; D013779:Tetrodotoxin / Q000494:pharmacology; D013936:Thymidine; D014701:Veratridine / Q000494:pharmacology*; D014702:Veratrine / Q000031:analogs & derivatives*
D013002:Somatomedins; D013779:Tetrodotoxin; D007334:Insulin-Like Growth Factor I; D014701:Veratridine; D012964:Sodium; D014702:Veratrine; D011188:Potassium; D013936:Thymidine