Ba2+ current oscillations modulated by cyclic AMP and phorbol esters in ras-transformed fibroblasts.
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.
Higashida
H
H
Department of Biophysics, Kanazawa University School of Medicine, Japan.
Hoshi
N
N
Noda
M
M
Shahidullah
M
M
Hashii
M
M
Nozawa
Y
Y
D016475:3T3 Cells; D000818:Animals; D001464:Barium / Q000494:pharmacology*; D001920:Bradykinin / Q000494:pharmacology; D003994:Bucladesine / Q000494:pharmacology*; D002461:Cell Line, Transformed; D005576:Colforsin / Q000494:pharmacology*; D000242:Cyclic AMP / Q000378:metabolism*; D005071:Evoked Potentials / Q000187:drug effects; D011905:Genes, ras; D007700:Kinetics; D007708:Kirsten murine sarcoma virus / Q000235:genetics; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology; D010703:Phorbol Esters / Q000494:pharmacology*; D013997:Time Factors
D010703:Phorbol Esters; D005576:Colforsin; C008876:phorbol-12,13-didecanoate; D001464:Barium; D015240:Phorbol 12,13-Dibutyrate; D003994:Bucladesine; D000242:Cyclic AMP; D001920:Bradykinin