Tooth pulp stimulation induces c-fos expression in the lateral habenular nucleus of the cat.
Detection of Fos protein expression by the peroxidase-antiperoxidase method was used to determine the area in the habenular (Hb) complex responding to electrical stimulation of the tooth pulp in the cat anaesthetized with pentobarbital. In the anaesthetic-injected group, the Fos-positive neurones were found bilaterally in the lateral Hb nucleus (HbL). Tooth pulp stimulation (intensity: 3 times the threshold for jaw-opening reflex) increased the number of positive neurones within the HbL by up to 300%, but did not induce any expression in the medical Hb nucleus. The increase in HbL was inhibited by morphine (2 mg kg-1, i.p.). These findings and the results of previous research suggest that HbL neurones are involved in defensive mechanisms by means of antinociception following noxious stimulation.
Matsumoto
N
N
Department of Oral-Physiology, School of Dentistry, Iwate Medical University, Japan.
Yahata
F
F
Kawarada
K
K
Kamata
K
K
Suzuki
T A
TA
D000818:Animals; D002415:Cats; D003782:Dental Pulp / Q000502:physiology*; D004558:Electric Stimulation; D005260:Female; D007150:Immunohistochemistry; D008297:Male; D009020:Morphine / Q000494:pharmacology; D009474:Neurons / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D013788:Thalamus / Q000166:cytology / Q000502:physiology*; D014018:Tissue Distribution
D016760:Proto-Oncogene Proteins c-fos; D009020:Morphine