Periodicity in Na(+) channel properties alters excitability of a model neuron.
The voltage gated Na channels play vital role in action potential waveform shaping and propagation. We have shown earlier that the duration and amplitude of a prolonged depolarization alter all the steady state and kinetic parameters of rNa(v)1.2a voltage gated Na channel in a pseudo-oscillatory fashion. In the present study, we show that the Hodgkin-Huxley voltage and time dependent rate constants of activation (alpha(m) and beta(m)) and fast inactivation (alpha(h) and beta(h)), obtained from the analyses of Na currents and steady state activation and inactivation plots, following application of prepulses in both slow (1-100s) and fast (100-1000ms) ranges, vary with the duration of a prepulse in a pseudo-oscillatory manner. Using these Hodgkin-Huxley kinetic parameters in simulation, the excitability and firing pattern of a model neuron are shown to vary in a history dependent periodic fashion.
Majumdar
Sriparna
S
Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India.
Sikdar
Sujit K
SK
D000200:Action Potentials / Q000502:physiology*; D001683:Biological Clocks / Q000502:physiology*; D003198:Computer Simulation; D004056:Differential Threshold / Q000502:physiology; D008564:Membrane Potentials / Q000502:physiology*; D008959:Models, Neurological; D015222:Sodium Channels / Q000502:physiology*
D015222:Sodium Channels