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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

A Negative Slope Conductance of the Persistent Sodium Current Prolongs Subthreshold Depolarizations

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Author(s):
Ceballos, Cesar C. [1, 2] ; Roque, Antonio C. [2] ; Leao, Ricardo M. [1]
Total Authors: 3
Affiliation:
[1] Univ Sao Paulo, Sch Med Ribeirao Preto, Dept Physiol, Ribeirao Preto - Brazil
[2] Univ Sao Paulo, Sch Philosophy Sci & Letters, Dept Phys, Ribeirao Preto - Brazil
Total Affiliations: 2
Document type: Journal article
Source: BIOPHYSICAL JOURNAL; v. 113, n. 10, p. 2207-2217, NOV 21 2017.
Web of Science Citations: 7
Abstract

Neuronal subthreshold voltage-dependent currents determine membrane properties such as the input resistance (Rin) and the membrane time constant (tm) in the subthreshold range. In contrast with classical cable theory predictions, the persistent sodium current (INaP), a non-inactivating mode of the voltage-dependent sodium current, paradoxically increases Rin and tm when activated. Furthermore, this current amplifies and prolongs synaptic currents in the subthreshold range. Here, using a computational neuronal model, we showed that the creation of a region of negative slope conductance by INaP activation is responsible for these effects and the ability of the negative slope conductance to amplify and prolong Rin and tm relies on the fast activation of INaP. Using dynamic clamp in hippocampal CA1 pyramidal neurons in brain slices, we showed that the effects of INaP on Rin and tm can be recovered by applying an artificial INaP after blocking endogenous INaP with tetrodotoxin. Furthermore, we showed that injection of a pure negative conductance is enough to reproduce the effects of INaP on Rin and tm and is also able to prolong artificial excitatory post synaptic currents. Since both the negative slope conductance and the almost instantaneous activation are critical for producing these effects, the INaP is an ideal current for boosting the amplitude and duration of excitatory post synaptic currents near the action potential threshold. (AU)

FAPESP's process: 16/01607-4 - High intensity sound stimulation and synaptic plasticity
Grantee:Ricardo Mauricio Xavier Leão
Support Opportunities: Regular Research Grants
FAPESP's process: 13/07699-0 - Research, Innovation and Dissemination Center for Neuromathematics - NeuroMat
Grantee:Oswaldo Baffa Filho
Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC