Mapping of c-Fos in the trigeminal sensory nucleus following high- and low-intensity afferent stimulation in the rat

Citation
M. Takemura et al., Mapping of c-Fos in the trigeminal sensory nucleus following high- and low-intensity afferent stimulation in the rat, EXP BRAIN R, 130(2), 2000, pp. 113-123
Citations number
57
Categorie Soggetti
Neurosciences & Behavoir
Journal title
EXPERIMENTAL BRAIN RESEARCH
ISSN journal
00144819 → ACNP
Volume
130
Issue
2
Year of publication
2000
Pages
113 - 123
Database
ISI
SICI code
0014-4819(200001)130:2<113:MOCITT>2.0.ZU;2-Z
Abstract
Although previous studies have suggested that nociceptive afferents from in tra-oral and facial structures are organized differently in the trigeminal sensory nucleus (TSN), more detailed data are needed. The present study aim ed to fill this gap, by examining the changes in the expression of c-Fos wi thin the rat TSN following high- and low-intensity electrical stimulation a pplied to the Gasserian ganglion (GG). A low-intensity stimulus (0.1 mA) in duced c-Fos in many neurons in the dorsomedial subdivision (Vodm) of the or al subnucleus (Vo; mean+/-SEM in a certain segment=163.0+/-42.7), in the me dial part of the dorsomedial subdivision (Vidm) of the interpolar subnucleu s (Vi; 120.5+/-40.1), in the medial corner of the magnocellular zone (VcIII /IV; 47.5+/-10.5), and in the superficial layers (VcI/II; 1330.0+/-65.6) al ong the entire length of the dorsomedial-ventrolateral axis of the caudal s ubnucleus (Vc). A modest number of Fos-positive neurons were induced in the dorsal principal subnucleus (Vp; 10.0+/-4.9) and in the lateral VcIIL/IV ( 11.5+/-1.6). A high-intensity stimulus (1.0 mA) significantly increased the number of Fos-positive neurons in each subdivision compared with the low-i ntensity stimulus (Vp 32.3+/-10.8; Vodm 270.3+/-75.3; Vidm 189.3+/-38.5; me dial VcIII/IV 77.5+/-18.2; lateral VcIII/IV 24.8+/-9.3; VcI/II, 2155.8+/-47 0.2). At both low- and high-intensity stimulation, the fields where Fos-pos itive neurons appeared are restricted to the dorsal or dorsomedial subdivis ions of the rostral subnuclei, Vp, Vo and Vi, where the main projectional f ields of primary afferents from the intraoral structures are found, while F os-positive neurons were distributed in the entire VcI/II, along the dorsom edial-ventrolateral axis of Vc, where the main projectional fields of prima ry afferents from the facial skin are found. The threshold to induce c-Fos is, however, different according to the fields. These results suggest that nociceptive processing in the intra-oral region is mediated through the ent ire length of the rostrocaudal axis of TSN, but is mediated primarily throu gh VcI/II in the facial region.