The cytoskeleton serves as a signal modulator for Ca
2+ and cAMP-regulated cell functions including the secretion of ions and granule contents. The interaction between Ca
2+ and cAMP signaling systems potentiates amylase secretion and suppresses Cl
- secretion in the parotid glands. In this study, we investigated the role of the cytoskeleton in the modulation of Cl
- and amylase secretion from rat parotid acinar cells upon activation of each intracellular signaling system and their interaction. Cytochalasin D markedly inhibited the Ca
2+-activated outwardly rectifying Cl
- current at positive membrane potentials and carbachol (CCh)-induced Cl
- currents in the whole-cell configuration at -80 mV, whereas colchicine enhanced Cl
- currents. Cytochalasin D, but not colchicine, markedly inhibited CCh-induced Cl
- secretion. Synergistic actions of CCh and forskolin on Cl
- and amylase secretion were observed even in the presence of cytochalasin D. These results suggest that the synergistic effects of Ca
2+ and cAMP signaling systems on amylase and Cl
- secretion do not require actin filament integrity but that secretion by the two signals themselves does require actin filament integrity.
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