title: Expression of P2X3 receptor in the trigeminal sensory nuclei of the rat.
abstract: Trigeminal primary afferents expressing P2X(3) receptor are involved in the transmission of orofacial nociceptive information. However, little is known about their central projection pattern and ultrastructural features within the trigeminal brainstem sensory nuclei (TBSN). Here we use multiple immunofluorescence and electron microscopy to characterize the P2X(3)-immunopositive (+) neurons in the trigeminal ganglion and describe the distribution and synaptic organization of their central terminals within the rat TBSN, including nuclei principalis (Vp), oralis (Vo), interpolaris (Vi), and caudalis (Vc). In the trigeminal ganglion, P2X(3) immunoreactivity was mainly in small and medium-sized somata, but also frequently in large somata. Although most P2X(3) (+) somata costained for the nonpeptidergic marker IB4, few costained for the peptidergic marker substance P. Most P2X(3) (+) fibers in the sensory root of trigeminal ganglion (92.9%) were unmyelinated, whereas the rest were small myelinated. In the TBSN, P2X(3) immunoreactivity was dispersed in the rostral TBSN but was dense in the superficial laminae of Vc, especially in the inner lamina II. The P2X(3) (+) terminals contained numerous clear, round vesicles and sparse large, dense-core vesicles. Typically, they were presynaptic to one or two dendritic shafts and also frequently postsynaptic to axonal endings, containing pleomorphic vesicles. Such P2X(3) (+) terminals, showing glomerular shape and complex synaptic relationships, and those exhibiting axoaxonic contacts, were more frequently seen in Vp than in any other TBSN. These results suggest that orofacial nociceptive information may be transmitted via P2X(3) (+) afferents to all TBSN and that it may be processed differently in different TBSN.
authors: Department of Oral Anatomy and Neurobiology, BK21, School of Dentistry, Kyungpook National University, Daegu 700-412, Korea.
authors: Yun Sook
authors: YS
authors: Kim
authors: Sang Kyoo
authors: SK
authors: Paik
authors: Yi Sul
authors: YS
authors: Cho
authors: Ho Seob
authors: HS
authors: Shin
authors: Jin Young
authors: JY
authors: Bae
authors: Masayuki
authors: M
authors: Moritani
authors: Atsushi
authors: A
authors: Yoshida
authors: Dong Kuk
authors: DK
authors: Ahn
authors: Juli
authors: J
authors: Valtschanoff
authors: Se Jin
authors: SJ
authors: Hwang
authors: Cheil
authors: C
authors: Moon
authors: Yong Chul
authors: YC
authors: Bae
mesh_terms: D000344:Afferent Pathways / Q000378:metabolism / Q000648:ultrastructure; D000818:Animals; D048429:Cell Size; D008297:Male; D016253:Microscopy, Immunoelectron; D036421:Nerve Fibers, Unmyelinated / Q000378:metabolism / Q000648:ultrastructure; D009475:Neurons, Afferent / Q000378:metabolism* / Q000648:ultrastructure; D009619:Nociceptors / Q000378:metabolism / Q000648:ultrastructure; D037121:Plant Lectins / Q000378:metabolism; D017729:Presynaptic Terminals / Q000378:metabolism / Q000648:ultrastructure; D051381:Rats; D017207:Rats, Sprague-Dawley; D018048:Receptors, Purinergic P2 / Q000378:metabolism*; D058477:Receptors, Purinergic P2X3; D013373:Substance P / Q000378:metabolism; D013569:Synapses / Q000378:metabolism / Q000648:ultrastructure; D013572:Synaptic Vesicles / Q000378:metabolism / Q000648:ultrastructure; D012668:Trigeminal Ganglion / Q000378:metabolism* / Q000648:ultrastructure; D014276:Trigeminal Nerve / Q000378:metabolism* / Q000648:ultrastructure; D014278:Trigeminal Nuclei / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: C045475:Griffonia simplicifolia lectins; C546410:P2rx3 protein, rat; D037121:Plant Lectins; D018048:Receptors, Purinergic P2; D058477:Receptors, Purinergic P2X3; D013373:Substance P