Developmental regulation of subtype-specific motor neuron excitability.
At early embryonic stages, zebrafish spinal neuron subtypes can be distinguished and accessed for physiological studies. This provides the opportunity to determine electrophysiological properties of different spinal motor neuron subtypes. Such differences have the potential to then regulate, in a subtype-specific manner, activity-dependent developmental events such as axonal outgrowth and pathfinding. The zebrafish spinal cord contains a population of early born neurons. Our recent work has revealed that primary motor neuron (PMN) subtypes in the zebrafish spinal cord differ with respect to electrical properties during early important periods when PMNs extend axons to their specific targets. Here, we review recent findings regarding the development of electrical properties in PMN subtypes. Moreover, we consider the possibility that electrical activity in PMNs may play a cell nonautonomous role and thus influence the development of later developing motor neurons. Further, we discuss findings that support a role for a specific sodium channel isoform, Nav1.6, expressed by specific subtypes of spinal neurons in activity-dependent processes that impact axonal outgrowth and pathfinding.
Moreno
Rosa L
RL
Department of Physiology and Biophysics, University of Colorado at the Anschutz Medical Center, Aurora, Colorado, USA. rosa.moreno@ucdenver.edu
Ribera
Angeles B
AB
D000557:Ambystoma / Q000502:physiology; D000818:Animals; D004330:Drosophila; D004594:Electrophysiology; D008160:Lumbosacral Plexus / Q000166:cytology / Q000502:physiology; D009046:Motor Neurons / Q000166:cytology / Q000502:physiology*; D018482:Muscle, Skeletal / Q000294:innervation; D062557:NAV1.6 Voltage-Gated Sodium Channel; D009424:Nervous System Physiological Phenomena; D009474:Neurons / Q000166:cytology / Q000502:physiology; D051381:Rats; D015222:Sodium Channels / Q000502:physiology; D013116:Spinal Cord / Q000166:cytology / Q000254:growth & development / Q000502:physiology; D015027:Zebrafish; D029961:Zebrafish Proteins / Q000502:physiology
D062557:NAV1.6 Voltage-Gated Sodium Channel; D015222:Sodium Channels; D029961:Zebrafish Proteins; C515010:scn8aa protein, zebrafish