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Cell division, ciliary regeneration and cyclic amp in a unicellular system

1973; Wiley; Volume: 82; Issue: 1 Linguagem: Inglês

10.1002/jcp.1040820105

1097-4652

Jason J. Wolff,

Neonatal Respiratory Health Research

Abstract It is possible, by direct measurements, to demonstrate the presence of cyclic AMP in Tetrahymena. Its presence in a unicellular eukaryote suggests a fundamental role in cellular metabolism independent of its function as a “second messenger.” Caffeine, an inhibitor of phosphodiesterase, raises the intracellular concentration of cyclic AMP and causes an inhibition of cellular division. Dibutyryl cyclic AMP also causes a partial inhibition of proliferation and is potentiated by caffeine. Inhibited cells do not recover spontaneously during continued exposure to caffeine but the inhibition is reversible resulting in a synchronous wave of division peaking one generation time after return to fresh medium. Synchronous cells subjected to pulses of caffeine at various intervals of the cell cycle are set back in time as measured by the excess division delay. There is a linear relationship between the age of the cells at the pulse and the duration of the excess division delay such that the older the cells are the greater is the setback. Caffeine and dibutyryl cyclic AMP inhibit ciliary regeneration as does also deuterium oxide.