B. Nikodijevic et al., CHARACTERISTICS OF THE K-252A-INDUCED INCREASE IN CALCIUM-UPTAKE IN PC12 CELLS, Journal of neuroscience research, 40(4), 1995, pp. 494-498
K-252a treatment produced a 30-50% increase in the uptake of radioacti
ve calcium by PC12 cells within 3-4 minutes. The increase in uptake wa
s partially blocked by inhibitors of voltage-operated calcium channels
, such as nifedipine, but not by inhibitors of receptor-operated calci
um channels, such as nickel or suramin. Introduction of phosphatase 2A
into the cells completely blocked the effect of K-252a. Long-term tre
atment of the cells with either K-252a or with nerve growth factor blo
cked the subsequent actions of either K-252a or nerve growth factor on
calcium uptake, but neither altered the subsequent action of the L-ch
annel agonist Bay K 8644 on calcium uptake. Calcium uptake was not sti
mulated by K-252a in PC12nnr, cells that have little or no high-affini
ty nerve growth factor receptors; cells expressing increased levels of
high-affinity nerve growth factor receptors showed a response to K-25
2a comparable to that seen in parent PC12. The data suggest that the i
ncreased uptake of radioactive calcium produced by K-252a is mediated
by a mechanism very similar to that serving the increased calcium upta
ke produced by nerve growth factor. (C) 1995 Wiley-Liss, Inc.