Trigeminal expression of N-methyl-D-aspartate receptor subunit 1 and behavior responses to experimental tooth movement in rats.
OBJECTIVE
To test the hypothesis that peripheral N-methyl-D-aspartate (NMDA) receptors play a role in pain induced by experimental tooth movement.


METHODS
Male Sprague-Dawley rats weighing between 200 g and 300 g were used in this study. Expression of NMDA receptors subunit 1 (NMDAR1) in the mandibular portion of the trigeminal ganglion (TG) was determined by Western blotting 4 hours and 1, 2, 3, 5, 7, and 14 days after tooth movement. Changes in the time taken by the rats on nocifensive behavior then effects of NMDA receptor antagonist MK-801 and force magnitude on these changes in behavior and NMDAR1 expression were evaluated.


RESULTS
Experimental tooth movement led to a statistically significant increase in NMDAR1 expression at protein level from day 1 to 7 after force application initiating tooth movement. Time spent on nocifensive behavior dramatically increased from day 1 to 7. The rhythm in NMDAR1 expression in the TG and behavioral activities correlated well with the initial orthodontic pain responses. The magnitude of the nocifensive behavior and NMDAR1 expression were both force magnitude dependent and could be reduced by peripheral NMDA receptor antagonist MK-801.


CONCLUSIONS
The hypothesis is accepted. Peripheral NMDA receptors are modulated by experimental tooth movement and involved in the development of tooth movement pain.
Yang
Zhi
Z
State Key Laboratory of Oral Diseases, Department of Orthodontics, West China College of Stomatology, Sichuan University, Chengdu, China.
Wang
Yan
Y
Luo
Wei
W
Hua
Xiaochuan
X
Wamalwa
Peter
P
Wang
Jing
J
Zhao
Zhihe
Z
Lu
Yun
Y
Liao
Zhengyu
Z
Lai
Wenli
W
D000818:Animals; D003799:Dental Stress Analysis; D016291:Dizocilpine Maleate / Q000493:pharmacokinetics; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D006120:Grooming / Q000187:drug effects; D008297:Male; D010146:Pain / Q000378:metabolism; D010147:Pain Measurement / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000096:biosynthesis*; D014087:Tooth Movement Techniques; D012668:Trigeminal Ganglion / Q000378:metabolism*
D016291:Dizocilpine Maleate; D018691:Excitatory Amino Acid Antagonists; D016194:Receptors, N-Methyl-D-Aspartate