Skip to main content
. Author manuscript; available in PMC: 2017 Dec 12.
Published in final edited form as: J Neurophysiol. 2006 May 17;96(3):1158–1170. doi: 10.1152/jn.01088.2005

FIG. 5.

FIG. 5

DOI rescues healthy motoneurons with no Na PIC and enables them to generate repetitive firing with slow current ramps. Sections A–D are recordings from the same cell. A: motoneuron from acute spinal rat recorded in nimodipine. Same format as in Fig. 4A. Slow current ramps well past normal threshold (Vth, horizontal dashed line measured in DOI) did not initiate action potentials or repetitive firing. Inset: full-height action potential triggered by current step. B: no Na PIC observed in voltage-clamp ramp before DOI. C: in this cell, DOI enabled repetitive firing with normal speed current ramps. D: onset of repetitive firing occurred at same time as facilitation of the Na PIC. E and F: same format as in A–D, but from an unusual chronic spinal rat motoneuron that did not exhibit any Na PIC when recorded in nimodipine. DOI facilitated self-sustained repetitive firing and slow firing (*) during current ramps (G), and induced a Na PIC large enough to produce a negative-slope region during voltage ramps (H).