Effects of corticotrophin on pain behavior and BDNF, CRF levels in frontal cortex of rats suffering from chronic pain.
OBJECTIVE
To investigate the effects of corticotrophin (Cor) on corticotropin-releasing factor (CRF), brain-derived neurotrophic factor (BDNF), and its functional receptor trkB in the frontal cortex of complete Freud's adjuvant (CFA)-induced arthritic rats.


METHODS
The chronic pain rat model was modified and pain behaviour scores were assessed. BDNF-immunoreactivity (IR), trkB-IR, and CRF mRNA-positive neurons were measured by immunohistochemistry and in situ hybridization methods.


RESULTS
Compared with control rats, pain behavior scores, BDNF-IR, CRF mRNA-positive, trkB-IR, and BDNF/CRF mRNA double-labeling neurons in the contralateral frontal cortex of the arthritic rats increased significantly at 24 h after injection of CFA (P < 0.05), and these effects were decreased markedly by i.p. injection of Cor (P < 0.05). The decrease in pain behavior and BDNF-IR, CRF mRNA levels in frontal cortex of arthritic rats due to Cor were partly prevented by adrenalectomy (ADX).


CONCLUSIONS
The increment in BDNF and CRF levels in the contralateral frontal cortex of arthritic rats may be inhibited by corticotrophin.
Xu
H W
HW
Department of Physiology, Third Military Medical University, Chongqing 400038, China. xuhaiwei@mail.tmmu.com.cn
Li
X C
XC
Li
H D
HD
Ruan
H Z
HZ
Liu
Z Z
ZZ
D000324:Adrenocorticotropic Hormone / Q000494:pharmacology*; D000818:Animals; D001168:Arthritis / Q000378:metabolism / Q000503:physiopathology; D019208:Brain-Derived Neurotrophic Factor / Q000378:metabolism*; D002908:Chronic Disease; D003346:Corticotropin-Releasing Hormone / Q000235:genetics / Q000378:metabolism*; D005260:Female; D005625:Frontal Lobe / Q000378:metabolism*; D008297:Male; D010146:Pain / Q000378:metabolism* / Q000503:physiopathology; D010147:Pain Measurement; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D020813:Receptor, trkB / Q000378:metabolism
D019208:Brain-Derived Neurotrophic Factor; D012333:RNA, Messenger; D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone; D020813:Receptor, trkB