The role of Renshaw cells in locomotion: antagonism of their excitation from motor axon collaterals with intravenous mecamylamine

B. R. Noga, S. J. Shefchyk, J. Jamal, L. M. Jordan

Research output: Contribution to journalArticle

56 Scopus citations

Abstract

The contribution of Renshaw cell (RC) activity to the production of fictive locomotion in the mesencephalic preparation was examined using the nicotinic antagonist mecamylamine (MEC). After the i.v. administration of 3 doses of MEC (1.0 mg/kg) the following observations were made: 1) ventral root (VR) evoked discharge of RCs was decreased by up to 87.7%, 2) recurrent inhibitory postsynaptic potentials recorded in alpha motoneurons were greatly reduced or abolished, and 3) the rhythmic firing of RCs during the fictive step cycle was abolished in 83% of the cells examined. Locomotor drive potentials (LDPs) in motoneurons persisted during the fictive step cycle after MEC administration. Bursts of motoneuron firing during each fictive step cycle were characterized by increased frequency and number of spikes after MEC, although the burst duration was unaltered for similar step cycle lengths. A greater number and frequency of spikes per burst was also observed in Ia inhibitory interneurons (IaINs), which remained rhythmically active after MEC administration. It is concluded that Renshaw cells are not an integral part of the spinal central pattern generator for locomotion, nor do they control the timing of the motoneuron or IaIN bursts of firing during fictive locomotion. The data are consistent with a role for RCs in limiting the firing rates of motoneurons and IaINs during each burst.

Original languageEnglish (US)
Pages (from-to)99-105
Number of pages7
JournalExperimental Brain Research
Volume66
Issue number1
DOIs
StatePublished - Mar 1 1987
Externally publishedYes

Keywords

  • Fictive locomotion
  • Mecamylamine
  • Renshaw cells

ASJC Scopus subject areas

  • Neuroscience(all)

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