Persistent Sodium Currents Participate in Fictive Locomotion Generation in Neonatal Mouse Spinal Cord

• DOI: 10.1523/jneurosci.0124-07.2007
• Publication Date: 2007-04-25T16:38:41Z
• Authors: Guisheng Zhong; Mark A. Masino; Ronald M. Harris-...
• Keywords: Tonic (physiology); Interneuron; Riluzole

The persistent sodium current (I(Na(P))) has been implicated in the regulation of synaptic integration, intrinsic membrane properties, and rhythm generation many types neurons. We characterized I(Na(P)) commissural interneurons (CINs) neonatal (postnatal days 0-3) mouse spinal cord; it is activated at subthreshold potentials, inactivates slowly, can be blocked by low concentrations riluzole. role locomotor pattern was examined applying riluzole during fictive locomotion induced NMDA, serotonin, dopamine or stimulation cauda equina. Blockade marginal effects on frequency but progressively weakens rhythmic firing locomotor-related oscillation CINs motoneurons (MNs) locomotor-like bursts ventral roots, until motor ceases. Riluzole directly affects properties MNs, reducing their ability to fire repetitively tonic depolarizations raising spike threshold. At same time, little strength spike-evoked transmission onto MNs. Our results suggest that essential for acts part regulating interneuron central generator locomotion.