Several types of sodium-conducting channel in human carcinoma A-431 cells.
Patch clamp method in outside-out configuration was used to search for cation channels which possibly mediate sodium influx through plasma membrane in A-431 carcinoma cells. We found four types of nonvoltage-gated Na-conducting channel. The first of 9-10 pS conductance (145 mM Na+, 30 degrees C) seems to be Na-selective; three others were characterized with conductance values of 24, 35 and 65 pS and lower selectivity among cations. Na-selective channels (9-10 pS) were not blocked by tetrodotoxin (1 microM). External application of amiloride (0.1-2 mM) resulted in a reversible inhibition of single currents through Na-selective channels.
Negulyaev YuA
Institute of Cytology, Russian Academy of Sciences, St. Petersburg.
Vedernikova
E A
EA
Mozhayeva
G N
GN
D000584:Amiloride / Q000494:pharmacology; D002294:Carcinoma, Squamous Cell / Q000737:chemistry*; D002462:Cell Membrane / Q000737:chemistry; D004563:Electrochemistry; D006801:Humans; D015222:Sodium Channels / Q000032:analysis*; D013779:Tetrodotoxin / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D015222:Sodium Channels; D013779:Tetrodotoxin; D000584:Amiloride