Single-channel analysis of Pb2+ modified steady-state Na-conductance in snail neurons.
Patch-clamp technique was used in order to study properties of the steady-state Na-channel in snail neurons. Experiments revealed that Pb-ions, applied extracellularly, close these channels, which are preferably in open state at the resting membrane potential. Elementary currents have a linear current-voltage (I-V) relationship with single channel conductance of 14 pS between -100 and -40 mV both in control saline and in the presence of 50 microM Pb in the pipette. Pb-ions decreased the mean open and increased the mean closed time. It was found that both open and closed times showed little voltage-dependence, however the probabilities of the open and closed times proved to be voltage-dependent. Open and closed time histograms were fitted by one exponential, therefore first order kinetics were assumed for the blocking effect of Pb2+ at the single channel level.
Osipenko
O N
ON
Department of General Physiology of Nervous System, A.A. Bogomoletz Institute of Physiology, Academy of Sciences of the Ukrainian S.S.R.
Kiss
T
T
D000818:Animals; D004553:Electric Conductivity; D007854:Lead / Q000737:chemistry*; D008564:Membrane Potentials / Q000502:physiology; D009474:Neurons / Q000737:chemistry / Q000502:physiology*; D012908:Snails; D015222:Sodium Channels / Q000502:physiology*
D015222:Sodium Channels; D007854:Lead