title: Origin and fine structure of substance P-containing nerve terminals in the facial nucleus of the rat: an immunohistochemical study.
abstract: The distribution, origin and fine structure of substance P-like immunoreactive (SPI) nerve terminals in the facial nucleus of the rat were investigated by means of immunocytochemistry. SPI-terminals were concentrated in the intermediate and dorsal subnuclei of the facial nucleus. Hemi-transection of the brainstem just rostral to the facial nucleus or at the most caudal level of the medulla oblongata did not cause any change of SPI-terminals in the facial nucleus. Electrical destruction of the various parts of the medulla oblongata clearly demonstrated that SPI-terminals in the intermediate subnucleus were supplied contralaterally from the SPI-neurons in the dorsomedial part of the medullary reticular formation. Most of the SPI-terminals (85%) in the intermediate subnucleus of the facial nucleus were observed to make asymmetric synaptic contacts with large dendrites (mean diameter; 1.26 micron). It was supposed that the contact sites are located on proximal parts of the dendrite. A few SPI-terminals (6%) formed axo-somatic contacts with large perikarya filled with numerous cytoplasmic organelles.
authors.forename: E
authors.initials: E
authors.lastname: Senba
authors.forename: M
authors.initials: M
authors.lastname: Tohyama
mesh_terms: D000818:Animals; D005154:Facial Nerve / Q000033:anatomy & histology / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D007124:Immunoenzyme Techniques; D008297:Male; D008854:Microscopy, Electron; D009434:Neural Pathways / Q000033:anatomy & histology; D011149:Pons / Q000033:anatomy & histology / Q000378:metabolism*; D051381:Rats; D013373:Substance P / Q000378:metabolism*; D013569:Synapses / Q000648:ultrastructure
chemical_list: D013373:Substance P