title: Ultrastructure of jaw muscle spindle afferents within the rat trigeminal mesencephalic nucleus.
abstract: This study examined the ultrastructures of neuronal elements within trigeminal mesencephalic nucleus by labeling masseteric mesencephalic neurons and masseter motoneurons with injection of horseradish peroxidase into masseteric muscle. Of eight horseradish peroxidase-labeled muscle spindle afferents examined, four terminals showed synaptic contact with labeled dendrites of masseteric motoneurons, two with labeled somata, and the remaining two with unlabeled dendrites. A few of the labeled dendrites showed intimate contact with the somata of the trigeminal mesencephalic nucleus neurons. These results provide morphological evidence of synaptic contact of recurring masseteric muscle spindle afferents with the trigeminal mesencephalic nucleus somata and also suggest the presence of electrical synapses between the somata of the trigeminal mesencephalic nucleus neurons and dendrites of jaw-closing motoneurons.
authors.affiliation: Department of Neurobiology, Graduate School of Dentistry, Kyungpook National University, Daegu, Korea.
authors.forename: Sang Kyoo
authors.initials: SK
authors.lastname: Paik
authors.forename: Myung Kyw
authors.initials: MK
authors.lastname: Kwak
authors.forename: Dong Kuk
authors.initials: DK
authors.lastname: Ahn
authors.forename: Young Kyung
authors.initials: YK
authors.lastname: Kim
authors.forename: Dong Sun
authors.initials: DS
authors.lastname: Kim
authors.forename: Cheil
authors.initials: C
authors.lastname: Moon
authors.forename: Masayuki
authors.initials: M
authors.lastname: Moritani
authors.forename: Atsushi
authors.initials: A
authors.lastname: Yoshida
authors.forename: Yong Chul
authors.initials: YC
authors.lastname: Bae
mesh_terms: D000818:Animals; D003712:Dendrites / Q000378:metabolism / Q000648:ultrastructure; D006735:Horseradish Peroxidase / Q000493:pharmacokinetics; D008406:Masseter Muscle / Q000187:drug effects / Q000294:innervation* / Q000378:metabolism; D046529:Microscopy, Electron, Transmission / Q000379:methods; D009046:Motor Neurons / Q000378:metabolism / Q000648:ultrastructure*; D009474:Neurons / Q000378:metabolism / Q000648:ultrastructure*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014278:Trigeminal Nuclei / Q000166:cytology*
chemical_list: D006735:Horseradish Peroxidase