Disruption of glial function enhances electroacupuncture analgesia in arthritic rats.
Activated glia play a major role in mediating behavioral hypersensitive state following peripheral inflammation. Electroacupuncture is well known to relieve persistent inflammatory pain. The present study was undertaken to examine whether fluorocitrate, a glial metabolic inhibitor, could synergize electroacupuncture antagonizing thermal hyperalgesia and mechanical allodynia evoked by ankle joint inflammation. Monoarthritis of rat ankle joint was induced by an intra-articular injection of Complete Freund's Adjuvant (CFA). The paw withdrawal latency (PWL) from a thermal stimulus and paw withdrawal threshold (PWT) from von Frey hairs were measured in awake rats. Intrathecal (i.t.) injection of 1 nmol fluorocitrate markedly suppressed monoarthritis-induced thermal hyperalgesia and mechanical allodynia. Unilateral electroacupuncture stimulation of "Huantiao" (GB30) and "Yanglingquan" (GB34) acupuncture points (100/2 Hz alternation, 1-2-3 mA) significantly elevated the PWLs and PWTs for 45 min after cessation of electroacupuncture in monoarthritic rats. Co-application of 0.1 or 1 nmol fluorocitrate with electroacupuncture significantly potentiated electroacupuncture analgesia, although 0.1 nmol fluorocitrate alone had no effect on PWLs and PWTs in monoarthritic rats. These results suggested that electroacupuncture and disrupting glial function could synergistically antagonize inflammatory pain, which might provide a potential strategy for the treatment of arthritic pain.
Sun
Shan
S
Institute of Neurobiology, Fudan University, 220 Handan Road, Shanghai 200433, China.
Chen
Wen-Ling
WL
Wang
Pei-Fen
PF
Zhao
Zhi-Qi
ZQ
Zhang
Yu-Qiu
YQ
D000704:Analysis of Variance; D000818:Animals; D001168:Arthritis / Q000150:complications / Q000209:etiology / Q000473:pathology* / Q000628:therapy*; D002951:Citrates / Q000008:administration & dosage; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D015671:Electroacupuncture / Q000379:methods*; D005620:Freund's Adjuvant; D007839:Functional Laterality; D006930:Hyperalgesia / Q000209:etiology / Q000628:therapy; D008297:Male; D009457:Neuroglia / Q000187:drug effects / Q000502:physiology*; D010146:Pain / Q000209:etiology; D059408:Pain Management; D010147:Pain Measurement / Q000379:methods; D017288:Pain Threshold / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D013997:Time Factors
D002951:Citrates; C007744:fluorocitrate; D005620:Freund's Adjuvant