Expression of P2X3 receptor in the trigeminal sensory nuclei of the rat.
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.
Kim
Yun Sook
YS
Department of Oral Anatomy and Neurobiology, BK21, School of Dentistry, Kyungpook National University, Daegu 700-412, Korea.
Paik
Sang Kyoo
SK
Cho
Yi Sul
YS
Shin
Ho Seob
HS
Bae
Jin Young
JY
Moritani
Masayuki
M
Yoshida
Atsushi
A
Ahn
Dong Kuk
DK
Valtschanoff
Juli
J
Hwang
Se Jin
SJ
Moon
Cheil
C
Bae
Yong Chul
YC
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
C045475:Griffonia simplicifolia lectins; C546410:P2rx3 protein, rat; D037121:Plant Lectins; D018048:Receptors, Purinergic P2; D058477:Receptors, Purinergic P2X3; D013373:Substance P