TY - JOUR
T1 - Distribution of fos‐like immunoreactivity in the caudal brainstem of the rat following noxious chemical stimulation of the temporomandibular joint
AU - Hathaway, Charles B.
AU - Hu, James W.
AU - Bereiter, David A.
PY - 1995/6/5
Y1 - 1995/6/5
N2 - Central expression of the protooncogene c‐fos was used to examine areas receiving noxious sensory input from the rat temporomandibular joint (TMJ). Fos‐like immunoreactivity (Fos‐LI) in the caudal brainstem was visualized 2 hours after unilateral injection of the small‐fiber‐specific excitant /inflammatory irritant mustard oil into the TMJ region. Control animals received injection of either mustard oil into the subcutaneous fascia overlying the masseter muscle or mineral oil vehicle into the TMJ region. In all groups, Fos‐LI was consistently observed ipsilaterally in the spinal trigeminal nucleus and cervical dorsal horn and, bilaterally, in the nucleus of the solitary tract and. the ventrolateral medulla. The expression of Fos‐LI ipsilaterally in the paratrigeminal nucleus was variable. Within the trigeminal sensory complex, Fos‐LI was restricted to subnucleus caudalis and the caudal portions of subnucleus interpolaris near the level of the obex. Approximately 12% of Fos‐LI cells in subnucleus caudalis and in the cervical dorsal horn were found in laminae III‐VI. Compared to TMJ mustard oil injection, mineral oil injection produced less Fos‐LI at all rostrocaudal levels, whereas subcutaneous mustard oil injection produced less Fos‐LI in caudal subnucleus caudalis but similar amounts in the cervical dorsal horn. Neither of these injections yielded significant ipsilateral responses in subnucleus caudalis, indicating that Fos‐LI in this region following TMJ mustard oil injection could be ascribed solely to small‐fiber stimulation in the deep TMJ region. The wide rostrocaudal distribution of Fos‐LI within the caudal brainstem reflects the distribution of TMJ‐responsive nociceptive neurons that may underlie the spread and referral of pain from the TMJ region. © 1995 Wiley‐Liss, Inc.
AB - Central expression of the protooncogene c‐fos was used to examine areas receiving noxious sensory input from the rat temporomandibular joint (TMJ). Fos‐like immunoreactivity (Fos‐LI) in the caudal brainstem was visualized 2 hours after unilateral injection of the small‐fiber‐specific excitant /inflammatory irritant mustard oil into the TMJ region. Control animals received injection of either mustard oil into the subcutaneous fascia overlying the masseter muscle or mineral oil vehicle into the TMJ region. In all groups, Fos‐LI was consistently observed ipsilaterally in the spinal trigeminal nucleus and cervical dorsal horn and, bilaterally, in the nucleus of the solitary tract and. the ventrolateral medulla. The expression of Fos‐LI ipsilaterally in the paratrigeminal nucleus was variable. Within the trigeminal sensory complex, Fos‐LI was restricted to subnucleus caudalis and the caudal portions of subnucleus interpolaris near the level of the obex. Approximately 12% of Fos‐LI cells in subnucleus caudalis and in the cervical dorsal horn were found in laminae III‐VI. Compared to TMJ mustard oil injection, mineral oil injection produced less Fos‐LI at all rostrocaudal levels, whereas subcutaneous mustard oil injection produced less Fos‐LI in caudal subnucleus caudalis but similar amounts in the cervical dorsal horn. Neither of these injections yielded significant ipsilateral responses in subnucleus caudalis, indicating that Fos‐LI in this region following TMJ mustard oil injection could be ascribed solely to small‐fiber stimulation in the deep TMJ region. The wide rostrocaudal distribution of Fos‐LI within the caudal brainstem reflects the distribution of TMJ‐responsive nociceptive neurons that may underlie the spread and referral of pain from the TMJ region. © 1995 Wiley‐Liss, Inc.
KW - c‐fos
KW - dorsal horn
KW - nociception
KW - pain
KW - spinal trigeminal nucleus
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U2 - 10.1002/cne.903560311
DO - 10.1002/cne.903560311
M3 - Article
C2 - 7642805
AN - SCOPUS:0028988699
SN - 0021-9967
VL - 356
SP - 444
EP - 456
JO - Journal of Comparative Neurology
JF - Journal of Comparative Neurology
IS - 3
ER -