Monosynaptic transmission of respiratory drive to phrenic motoneurons from brainstem bulbospinal neurons in rats

J Comp Neurol. 1988 Mar 1;269(1):47-57. doi: 10.1002/cne.902690104.


The termination patterns in the rat phrenic nucleus of neurons within two respiratory cell groups of the ventrolateral medulla (Bötzinger Complex and the rostral ventral respiratory group) were determined. The plant lectin, Phaseolus vulgaris leuco-agglutinin, was used as an anterograde tracer to label presynaptic processes of bulbospinal neurons, and horseradish peroxidase was used simultaneously to label phrenic motoneurons. Labeled bulbospinal axons ended with dense terminal arborizations within the phrenic cell column and on radial phrenic motoneuron dendrite bundles, which represented the exclusive site of termination of Bötzinger Complex and rostral ventral respiratory group neurons in the lower cervical spinal cord. Terminals of these descending axons formed presumptive synaptic contacts within longitudinal and radial dendrite bundles, and on the cell somata of phrenic motoneurons.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Afferent Pathways / anatomy & histology
  • Afferent Pathways / physiology
  • Animals
  • Motor Neurons / cytology
  • Motor Neurons / physiology*
  • Phrenic Nerve / cytology
  • Phrenic Nerve / physiology*
  • Phytohemagglutinins
  • Rats
  • Rats, Inbred Strains
  • Reflex, Monosynaptic*
  • Respiratory Center / anatomy & histology
  • Respiratory Center / physiology*
  • Spinal Cord / cytology
  • Spinal Cord / physiology*


  • Phytohemagglutinins