REGULAR ARTICLES
Cell Research (1998)8:23-31
© 1998 SIBS, CAS All rights reserved 1001-0602/98
Types of voltage-dependent calcium channels involved in high
potassium depolarization-induced amylase secretion in the exocrine pancreatic
tumour cell line AR4-2J.
Cui ZJ.
Beijing Agricultural University Faculty of Biological Sciences, China.
In the perifused fura-2 loaded exocrine pancreatic acinar cell line AR4-2J
pulses of high potassium induced repetitive increases in intracellular calcium.
Attached cells when stimulated with high potassium secreted large amount
of amylase. High potassium-induced secretion was dependent both on the concentration
of potassium and duration of stimulation. High potassium induced increases
in intracellular calcium were inhibited by voltage-dependent calcium channel
antagonists with an order of potency as follows: nifedipine > omega-agatoxin
IVA > omega-conotoxin GVIA. In contrast, the L-type calcium channel antagonist
nifedipine almost completely inhibited potassium-induced amylase secretion,
whereas the N-type channel antagonist omega-conotoxin GVIA was without effect.
The P-type channel antagonist omega-agatoxin IVA had a small inhibitory
effect, but this inhibition was not significant at the level of amylase
secretion. In conclusion, the AR4-2J cell line possesses different voltage-dependent
calcium channels (L, P, N) with the L-type predominantly involved in depolarization
induced amylase secretion.
Keywords : AR4-2J,
pancreatic acinar cells, amylase, secretion, calcium channels. |
