Short-term plasticity of descending synaptic input to phrenic motoneurons in rats

F. Hayashi, C. F.L. Hinrichsen, D. R. McCrimmon*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

35 Scopus citations

Abstract

Respiratory afferent stimulation can elicit increases in respiratory motor output that outlast the period of stimulation by seconds to minutes [short-term potentiation (STP)]. This study examined the potential contribution of spinal mechanisms to STP in anesthetized, vagotomized, paralyzed rats. After C1 spinal cord transection, stimulus trains (100 Hz, 5-60 s) of the C1-C2 lateral funiculus elicited STP of phrenic nerve activity that peaked several seconds poststimulation. Intracellular recording revealed that individual phrenic motoneurons exhibited one of three different responses to stimulation: 1) depolarization that peaked several seconds poststimulation, 2) depolarization during stimulation and then exponential repolarization after stimulation, and 3) bistable behavior in which motoneurons depolarized to a new, relatively stable level that was maintained after stimulus termination. During the STP, excitatory postsynaptic potentials elicited by single-stimulus pulses were larger and longer. In conclusion, repetitive activation of the descending inputs to phrenic motoneurons causes a short-lasting depolarization of phrenic motoneurons, and augmentation of excitatory postsynaptic potentials, consistent with a contribution to STP.

Original languageEnglish (US)
Pages (from-to)1421-1430
Number of pages10
JournalJournal of applied physiology
Volume94
Issue number4
DOIs
StatePublished - Apr 1 2003

Keywords

  • Bistability
  • Bulbospinal pathways
  • Central control of breathing
  • Short-term potentiation

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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