Identification of alpha and gamma trigeminal motoneurons by the vibratome paraplast technique for HRP histochemistry

Acta Anat (Basel). 1987;129(4):333-6. doi: 10.1159/000146425.


A morphometric analysis of the masseteric motoneuron pool of the trigeminal motor nucleus was performed in the rat using horseradish peroxidase as a marker. Thick (40 microns) cryosections and thin (7 microns) Paraplast sections were compared. Two types of motoneurons related to the masseter muscle were observed. Small motoneurons, which had a high nuclear index, were found interspersed between large motoneurons, which had more cytoplasm. Evidence is provided that the small trigeminal motoneurons are gamma neurons that innervate the intrafusal muscle fibers of the masseteric muscle spindles.

MeSH terms

  • Animals
  • Female
  • Histocytochemistry / methods*
  • Horseradish Peroxidase
  • Male
  • Masseter Muscle / innervation
  • Microtomy
  • Motor Neurons / classification
  • Motor Neurons / ultrastructure*
  • Rats
  • Trigeminal Ganglion / ultrastructure*
  • Trigeminal Nerve / ultrastructure*


  • Horseradish Peroxidase