Reduction of the same calcium current component by A and C kinases: differential pertussis toxin sensitivity.
Voltage-clamp techniques were used to study the effect of forskolin, 8-Br-cyclic AMP, and phorbol 12,13-dibutyrate (PDBu) on the 3 voltage-dependent calcium current components of mouse dorsal root ganglion neurons in culture. Forskolin and 8-Br-cyclic AMP selectively reduced the transient high-threshold (N-type) calcium current component, an effect also produced by PDBu, a C kinase activator. Pretreatment of cultures with pertussis toxin prevented the reduction of calcium current by PDBu, but was without effect on the reductions produced by forskolin or 8-Br-cyclic AMP. These results support the contention that activation of both A and C kinases selectively affect calcium currents in vertebrate neurons by reducing the N-type calcium current component. While the activation of the C kinase required a G protein to exert its effect, the activation of A kinase did not.
Gross
R A
RA
Department of Neurology, University of Michigan Medical Center, Ann Arbor 48104-1687.
Macdonald
R L
RL
D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D005576:Colforsin / Q000494:pharmacology; D004553:Electric Conductivity; D005071:Evoked Potentials / Q000187:drug effects; D005727:Ganglia, Spinal / Q000502:physiology; D007473:Ion Channels / Q000187:drug effects / Q000502:physiology*; D051379:Mice; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D037342:Pertussis Toxin; D015240:Phorbol 12,13-Dibutyrate; D010703:Phorbol Esters / Q000494:pharmacology; D011493:Protein Kinase C / Q000502:physiology*; D011494:Protein Kinases / Q000502:physiology*; D010566:Virulence Factors, Bordetella / Q000494:pharmacology*
D007473:Ion Channels; D010703:Phorbol Esters; D010566:Virulence Factors, Bordetella; D005576:Colforsin; D015124:8-Bromo Cyclic Adenosine Monophosphate; D015240:Phorbol 12,13-Dibutyrate; D037342:Pertussis Toxin; D011494:Protein Kinases; D011493:Protein Kinase C; D002118:Calcium