Control of calcium channels in neuroblastoma cells (N1E-115).
Neuroblastoma cells (N1E-115) were used as models of transient (T) and long-lasting (L) Ca++ channels. The whole cell version of the patch clamp technique was used to measure inward Ca++ currents, and the fluorescent indicator, Fura-2, was used to measure changes in intracellular Ca++. Cells were cultured and selected during recording so that predominantly T or L channel currents were measured. T channel currents did not respond to dihydropyridine or parathyroid hormone, whereas L channel currents did. BAY-K-8644 increased and nifedipine decreased L channel currents. After a 15 mM KCl challenge, cells with predominantly T channels responded with a transient change in intracellular Ca++, while cells with predominantly L channels showed a sustained response. PTH inhibited the increase in intracellular Ca++ in cells with L channels, but not in those with T channels. PTH may be an example of an endogenous calcium channel blocker, at least in neuroblastoma cells.
Pang
P K
PK
Department of Physiology, University of Alberta, Edmonton, Canada.
Wang
R
R
Wu
L Y
LY
Karpinski
E
E
Shan
J
J
Benishin
C G
CG
D002121:Calcium Channel Blockers / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism*; D004095:Dihydropyridines / Q000378:metabolism*; D006801:Humans; D009447:Neuroblastoma / Q000378:metabolism*; D009543:Nifedipine / Q000378:metabolism*; D010281:Parathyroid Hormone / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D004095:Dihydropyridines; D010281:Parathyroid Hormone; D009543:Nifedipine