Ba2+ current oscillations modulated by cyclic AMP and phorbol esters in ras-transformed fibroblasts. |
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Authors: | H Higashida N Hoshi M Noda M Shahidullah M Hashii Y Nozawa |
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Affiliation: | Department of Biophysics, Kanazawa University School of Medicine, Japan. |
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Abstract: | An oscillatory influx of divalent cations was measured as Ba2+ inward currents (Ba2+ current oscillations) by voltage-clamp recording in v-Ki-ras-transformed NIH/3T3 (DT) fibroblasts after activation with bradykinin or serum. Application of forskolin or dibutyryl cyclic AMP onto DT cells initiated Ba2+ current oscillations. Increasing intracellular cyclic AMP reduced the amplitude but increased the frequency of the Ba2+ current oscillations. Activation of protein kinase C by phorbol esters terminated Ba2+ current oscillations. No inhibition of Ba2+ current oscillations by phorbol esters was observed in down-regulated cells that had been pretreated with phorbol esters for 24 hrs. The results suggest that Ba2+ current oscillations are regulated by intracellular second messengers. |
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