Interaction of steroidal alkaloid toxins with calcium channels in neuronal cell lines.
Depolarization with 50 mM K+ increased 45Ca2+ uptake into neuronal clonal cell lines NG108-15, N1E-115 and NH15-CA2. In each cell line this depolarization-induced uptake was blocked by inorganic and organic blockers of voltage sensitive calcium channels. However, tetrodotoxin (10(-6) M) was ineffective. Moreover, in the presence of tetrodotoxin, neither batrachotoxin nor veratridine inhibited the depolarization-induced uptake. The novel dihydropyridine BAY K8644 enhanced depolarization-induced 45Ca2+ uptake into each cell line in a nitrendipine reversible fashion. In the presence of tetrodotoxin, the BAY K8644/50 mM K+ stimulated uptake could be partially inhibited by batrachotoxin (10(-6) M) and veratridine (5 X 10(-5) M). These effects were not altered by the presence of scorpion venom (1 microgram/ml). The results indicate that both batrachotoxin and veratridine can modulate the effects of dihydropyridines on the gating properties of voltage sensitive calcium channels.
Kongsamut
S
S
Freedman
S B
SB
Simon
B E
BE
Miller
R J
RJ
D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D001496:Batrachotoxins / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002132:Calcium Radioisotopes; D002460:Cell Line; D002999:Clone Cells; D004594:Electrophysiology; D005910:Glioma; D006822:Hybrid Cells; D007473:Ion Channels / Q000187:drug effects*; D009447:Neuroblastoma; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D009543:Nifedipine / Q000031:analogs & derivatives / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D014701:Veratridine / Q000494:pharmacology*; D014702:Veratrine / Q000031:analogs & derivatives*
D001496:Batrachotoxins; D002121:Calcium Channel Blockers; D002132:Calcium Radioisotopes; D007473:Ion Channels; D011725:Pyridines; D014701:Veratridine; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D014702:Veratrine; D009543:Nifedipine; D011188:Potassium; D002118:Calcium