title: Persistent sodium current decreases transient gain in turtle motoneurons.
abstract: Voltage dependent ion channels can influence signal integration in neurons dramatically. In addition to the classical fast-inactivating Na(+) current that mediates action potentials, many neurons also express persistent sodium current (I(NaP)). Activating at membrane potentials below the threshold for action potentials, this current may amplify excitatory postsynaptic potentials and shape the firing patterns. To determine the qualitative contribution of I(NaP) to the intrinsic firing properties of motoneurons, we eliminated this current by dynamic clamp. As expected, we found that elimination of I(NaP) shifted the rheobase to more positive currents. More interestingly, elimination of I(NaP) increased the steepness of initial frequency-to-current (fI) relation. This suggests that I(NaP) decreases the transient gain and broadens the integration window for short synaptic inputs in spinal motoneurons.
authors.affiliation: Department of Biochemistry and Biophysics, Faculty of Natural Sciences, Vilnius University, Ciurlionio 21, LT-03101 Vilnius, Lithuania.
authors.forename: Mantas
authors.initials: M
authors.lastname: Gabrielaitis
authors.forename: Rokas
authors.initials: R
authors.lastname: Buisas
authors.forename: Robertas
authors.initials: R
authors.lastname: Guzulaitis
authors.forename: Gytis
authors.initials: G
authors.lastname: Svirskis
authors.forename: Aidas
authors.initials: A
authors.lastname: Alaburda
mesh_terms: D000200:Action Potentials / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D055592:Biophysical Phenomena / Q000187:drug effects / Q000502:physiology*; D004558:Electric Stimulation / Q000379:methods; D066298:In Vitro Techniques; D009046:Motor Neurons / Q000187:drug effects / Q000502:physiology*; D018408:Patch-Clamp Techniques / Q000379:methods; D026941:Sodium Channel Blockers / Q000494:pharmacology; D015222:Sodium Channels / Q000187:drug effects / Q000502:physiology*; D013116:Spinal Cord / Q000166:cytology; D013779:Tetrodotoxin / Q000494:pharmacology; D014426:Turtles
chemical_list: D026941:Sodium Channel Blockers; D015222:Sodium Channels; D013779:Tetrodotoxin