PMID- 25807259
OWN - NLM
STAT- MEDLINE
DCOM- 20160304
LR  - 20181113
IS  - 1932-6203 (Electronic)
IS  - 1932-6203 (Linking)
VI  - 10
IP  - 3
DP  - 2015
TI  - Sex differences in peripheral mu-opioid receptor mediated analgesia in rat 
      orofacial persistent pain model.
PG  - e0122924
LID - 10.1371/journal.pone.0122924 [doi]
LID - e0122924
AB  - Unilateral ligation of the tendon of anterior superficial part of rat masseter 
      muscle (TASM) leads to long-lasting allodynia. Sex differences in peripheral 
      mu-opioid receptor (MOR)-mediated analgesia under persistent myogenic pain are 
      not well understood. In this study, we examined (1) whether locally applied MOR 
      agonists attenuate persistent pain following TASM ligation in a sex dependent 
      manner, (2) whether there are sex differences of MOR expression changes in rat 
      trigeminal ganglia (TG). The effects of MOR agonist, D-Ala2, N-Me-Phe4, 
      Gly5-ol]-Enkephalin acetate salt (DAMGO), were assessed 14 days after TASM 
      ligation in male, female and orchidectomized (GDX) male rats. MOR mRNA and 
      protein levels in TG 14 days following tendon ligation were also determined. The 
      mechanical thresholds of the injured side were significantly decreased in both 
      male and female rats, from 3 days to 28 days after TASM ligation. A10 mug DAMGO 
      significantly attenuated allodynia in male rats. A 10-fold higher dose of DAMGO 
      was required in female and GDX male rats to produce the level of anti- allodynia 
      achieved in male rats. The level of MOR mRNA in TG from male rats was 
      significantly greater 14 days after TASM ligation compared with the sham-operated 
      male rats, but not from female and GDX male rats. After TASM ligation, males had 
      significantly more MOR immunoreactivity in TG compared to sham-operated males. 
      The MOR levels increased to 181.8% of the sham level in male rats receiving 
      tendon injury. But there was no significant change in female rats receiving 
      tendon injury compared to the sham female rats. Taken together, our data suggest 
      that there were sex differences in the effects of peripheral MOR agonists between 
      male and female rats under TASM ligation developing long-lasting pain condition, 
      which is partly mediated by sex differences in the changes of MOR expressions and 
      testosterone is an important factor in the regulation of MOR.
FAU - Bai, Xiaofeng
AU  - Bai X
AD  - Associate Professor, Department of Oral and Maxillofacial Surgery, School & 
      Hospital of Stomatology, China Medical University, 117 North Nanjing Street, 
      Shenyang, P. R. of China, 110002.
FAU - Zhang, Xia
AU  - Zhang X
AD  - Associate Professor, Department of Anesthesiology, School & Hospital of 
      Stomatology, China Medical University, 117 North Nanjing Street, Shenyang, P. R. 
      of China, 110002.
FAU - Li, Yanshu
AU  - Li Y
AD  - Assistant Professor, Department of Cell Biology, China Medical University, 92 
      Bei'er Road, Shenyang, P. R. of China, 110001.
FAU - Lu, Li
AU  - Lu L
AD  - Professor, Department of Oral and Maxillofacial Surgery, School & Hospital of 
      Stomatology, China Medical University, 117 North Nanjing Street, Shenyang, P. R. 
      of China, 110002.
FAU - Li, Bo
AU  - Li B
AD  - Associate Professor, Department of Oral Anatomy and Physiology, School of 
      Stomatology, China Medical University, 117 North Nanjing Street, Shenyang, P. R. 
      of China, 110002.
FAU - He, Xiaofan
AU  - He X
AD  - Assistant Professor, Department of Anesthesiology, School & Hospital of 
      Stomatology, China Medical University, 117 North Nanjing Street, Shenyang, P. R. 
      of China, 110002.
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20150325
PL  - United States
TA  - PLoS One
JT  - PloS one
JID - 101285081
RN  - 0 (Analgesics, Opioid)
RN  - 0 (RNA, Messenger)
RN  - 0 (Receptors, Opioid, mu)
RN  - 100929-53-1 (Enkephalin, Ala(2)-MePhe(4)-Gly(5)-)
SB  - IM
MH  - Analgesics, Opioid/pharmacology/*therapeutic use
MH  - Animals
MH  - Behavior, Animal/drug effects
MH  - Disease Models, Animal
MH  - Enkephalin, Ala(2)-MePhe(4)-Gly(5)-/pharmacology/*therapeutic use
MH  - Facial Pain/*drug therapy/etiology/veterinary
MH  - Female
MH  - Hyperalgesia/drug therapy/etiology/pathology
MH  - Immunohistochemistry
MH  - Male
MH  - Orchiectomy
MH  - RNA, Messenger/metabolism
MH  - Rats
MH  - Rats, Sprague-Dawley
MH  - Real-Time Polymerase Chain Reaction
MH  - Receptors, Opioid, mu/agonists/genetics/*metabolism
MH  - Sex Characteristics
MH  - Tendon Injuries/complications/pathology
MH  - Trigeminal Ganglion/metabolism/pathology
PMC - PMC4373836
COIS- Competing Interests: The authors have declared that no competing interests exist.
EDAT- 2015/03/26 06:00
MHDA- 2016/03/05 06:00
PMCR- 2015/03/25
CRDT- 2015/03/26 06:00
PHST- 2014/08/30 00:00 [received]
PHST- 2015/02/16 00:00 [accepted]
PHST- 2015/03/26 06:00 [entrez]
PHST- 2015/03/26 06:00 [pubmed]
PHST- 2016/03/05 06:00 [medline]
PHST- 2015/03/25 00:00 [pmc-release]
AID - PONE-D-14-39023 [pii]
AID - 10.1371/journal.pone.0122924 [doi]
PST - epublish
SO  - PLoS One. 2015 Mar 25;10(3):e0122924. doi: 10.1371/journal.pone.0122924. 
      eCollection 2015.