Aconitine-induced modification of single sodium channels in neuroblastoma cell membrane.
Aconitine-modified sodium channels in the neuroblastoma cell membrane were investigated with patch-clamp technique in outside-out configuration. When aconitine (0.1 mmol/l) was present in the pipette solution two types of modified single sodium channels were observed. The first type showed openings with normal amplitude (slope conductance 15.5 pS) and bursting behaviour. The second type of modified channel openings was characterized with low amplitude (slope conductance 2.8 pS) and longer open time as comparing to unmodified channels. The low-amplitude channels were shown to have altered ion selectivity: they were permeable to NH4+. Both populations of aconitine-modified channels could be blocked by tetrodotoxin. In contrast to macroscopic current experiments (Mozhayeva et al. 1977) the development of aconitine modification was not affected by repetitive stimulation and external application of the agent had no effect on single sodium channels in outside-out membrane patch.
Negulyaev YuA
Institute of Cytology, Academy of Sciences of the USSR, Leningrad.
Vedernikova
E A
EA
Savokhina
G A
GA
D000157:Aconitine / Q000494:pharmacology*; D031841:Aconitum / Q000031:analogs & derivatives*; D000818:Animals; D002460:Cell Line; D004553:Electric Conductivity; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D009447:Neuroblastoma; D015222:Sodium Channels / Q000187:drug effects / Q000502:physiology*; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000502:physiology
D015222:Sodium Channels; D000157:Aconitine