title: Expression of glycine receptor alpha 3 in the rat trigeminal neurons and central boutons in the brainstem.
abstract: Increasing evidence shows that the homomeric glycine receptor is expressed in axon terminals and is involved in the presynaptic modulation of transmitter release. However, little is known about the expression of the glycine receptor, implicated in the presynaptic modulation of sensory transmission in the primary somatosensory neurons and their central boutons. To address this, we investigated the expression of glycine receptor subunit alpha 3 (GlyRα3) in the neurons in the trigeminal ganglion and axon terminals in the 1st relay nucleus of the brainstem by light- and electron-microscopic immunohistochemistry. Trigeminal primary sensory neurons were GlyRα3-immunopositive/gephyrin-immunonegative (indicating homomeric GlyR), whereas GlyRα3/gephyrin immunoreactivity (indicating heteromeric GlyR) was observed in dendrites. GlyRα3 immunoreactivity was also found in the central boutons of primary afferents but far from the presynaptic site and in dendrites at subsynaptic sites. Boutons expressing GlyRα3 contained small round vesicles, formed asymmetric synapses with dendrites and were immunoreactive for glutamate. These findings suggest that trigeminal primary afferent boutons receive presynaptic modulation via homomeric, extrasynaptic GlyRα3, and that different subtypes of GlyR may be involved in pre- and postsynaptic inhibition.
authors.affiliation: Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, 188-1, 2-Ga, Samdeok-Dong, Jung-Gu, Daegu, 700-412, South Korea.
authors.forename: Jin Young
authors.initials: JY
authors.lastname: Bae
authors.affiliation: Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, 188-1, 2-Ga, Samdeok-Dong, Jung-Gu, Daegu, 700-412, South Korea.
authors.forename: Won
authors.initials: W
authors.lastname: Mah
authors.affiliation: Korea Brian Research Institute, 61 Cheomdan-ro, Dong-gu, Daegu, 701-300, South Korea.
authors.forename: Jong-Cheol
authors.initials: JC
authors.lastname: Rah
authors.affiliation: Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, 188-1, 2-Ga, Samdeok-Dong, Jung-Gu, Daegu, 700-412, South Korea.
authors.forename: Sook Kyung
authors.initials: SK
authors.lastname: Park
authors.affiliation: Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, 188-1, 2-Ga, Samdeok-Dong, Jung-Gu, Daegu, 700-412, South Korea. ycbae@knu.ac.kr.
authors.forename: Yong Chul
authors.initials: YC
authors.lastname: Bae
mesh_terms: D000818:Animals; D001933:Brain Stem / Q000378:metabolism / Q000648:ultrastructure*; D002352:Carrier Proteins / Q000378:metabolism; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D017729:Presynaptic Terminals / Q000378:metabolism* / Q000648:ultrastructure*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018009:Receptors, Glycine / Q000378:metabolism*; D012668:Trigeminal Ganglion / Q000378:metabolism* / Q000648:ultrastructure*
chemical_list: D002352:Carrier Proteins; D008565:Membrane Proteins; D018009:Receptors, Glycine; C073441:gephyrin; C113965:glycine receptor alpha3 subunit
keywords: Extrasynaptic; Glycine receptor; Presynaptic modulation; Primary sensory afferent; Trigeminal; Ultrastructure