Nicardipine inhibits N-type calcium channels in dbcAMP-differentiated neuroblastoma x glioma hybrid cells (NG 108-15 cells).
OBJECTIVE
To investigate the possibility of dihydropyridine inhibition of N-type calcium channels.


METHODS
Effects of nifedipine and nicardipine on the high K(+)-induced intracellular Ca2+ concentration ([Ca2+]i) increase were studied by measuring [Ca2+]i using the fluorescent indicator Fura-2.


RESULTS
Pretreatment of cells with nifedipine 50 mumol.L-1 inhibited the high K(+)-induced [Ca2+]i transient by about 60% (n = 3); however, pretreatment of cells with nicardipine 10 mumol.L-1 completely prevented the high K(+)-evoked [Ca2+]i increase in dibutyryl cyclic AMP (dbcAMP)-differentiated NG 108-15 cells (n = 5). The high K(+)-induced [Ca2+]i increase was mediated by L- and N-type voltage-sensitive calcium channels (VSCC) in NG 108-15 cells.


CONCLUSIONS
Nicardipine at micromolar range inhibited both L- and N-type VSCC in dbcAMP-differentiated NG 108-15 cells whereas nifedipine mainly inhibited L-type calcium channels.
Li
S N
SN
Institute of Pharmacology and Toxicology, Dresden University of Technology, Germany. medp7082@nus.edu.sg
Bräter
M
M
Andreas
K
K
D003994:Bucladesine; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D015220:Calcium Channels / Q000187:drug effects*; D002471:Cell Transformation, Neoplastic / Q000187:drug effects; D005910:Glioma / Q000473:pathology; D006801:Humans; D006822:Hybrid Cells; D009447:Neuroblastoma / Q000473:pathology; D009529:Nicardipine / Q000494:pharmacology*; D009543:Nifedipine / Q000494:pharmacology; D014407:Tumor Cells, Cultured / Q000187:drug effects
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D003994:Bucladesine; D009529:Nicardipine; D009543:Nifedipine