Serum induces the immediate opening of Ca2+-activated channels in quiescent human fibroblasts.
Application of fetal calf serum to quiescent human fibroblasts produces an immediate (3-20 s delay) increase in membrane conductance which lasts about 20-30 s. This conductance is strongly outwardly-rectifying and has a reversal potential between -45 and -10 mV. The conductance increase may also be induced by application of the Ca2+ ionophore A23187 while it does not occur when intracellular K+ is replaced by Cs+. It is concluded that this early effect of serum is due to the opening of Ca2+-activated channels. This permeability change will alter the membrane potential and thus possibly interact with other voltage-sensitive processes induced by serum growth factors.
Peres
A
A
Dipartimento di Fisiologia e Biochimica Generali, Università di Milano, Italy.
Zippel
R
R
Sturani
E
E
D001769:Blood; D000001:Calcimycin / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology*; D003470:Culture Media; D004553:Electric Conductivity; D005347:Fibroblasts / Q000502:physiology; D006801:Humans; D007700:Kinetics; D008564:Membrane Potentials
D015220:Calcium Channels; D003470:Culture Media; D000001:Calcimycin