Abstract

HERNANDEZ BUSTOS, Oscar Emilio  and  HERNANDEZ BUSTOS, Lilibeth. Efect of the Kv3.1 potassium conductance in the firing frequency and firing rate of an unmyelinated axón. Salud, Barranquilla [online]. 2011, vol.27, n.2, pp.210-222. ISSN 0120-5552.

Objective: To determine the relationship between the Kv3.1 potassium conductance and the firing rate (Td) in a neuronal model called neuron1, consisting of a soma, a hillock and an unmyelinated axon, during a constant current stimulus 10ms long and at 40°c. Methodology: Using the free software neuron, the propagation of action potentials along a neuronal structure called neurona1 was simulated. The maximum Kv3.1 conductance (G_Kv31) relative to the maximum potassium conductance (G_k) studied in 1952 by a.l. Hodgkin and a.f. Huxley and in this paper called HH conductance, was varied such that G_k, +G_Kv3.1= 1.6s/cm2. Results: In a neuronal structure with the biophysical characteristics of neuronl, Td varies in a sigmoid way for all g_kv31such that 0<G_Kv31/G_k< 0.455 and drops exponentially for all g_kv31such that 0.455<G_Kv31/G_k<15. For the first case, Td is 11 times greater than frequency rate (f) in respect to the number of spikes in every action potential burst. Conclusion: The observation of Kv3.1 potassium conductance in some types of neurons does not necessary imply the propagation of high rate action potential bursts. Its effect is more pronounced (11 times) in the modulation of Td than in the increase off.

Keywords : Firing frequency; Rate frequency; Kv3.1 potassium conductance; Unmyelinated axon.

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