title: Electroacupuncture inhibits phosphorylation of spinal phosphatidylinositol 3-kinase/Akt in a carrageenan-induced inflammatory rat model.
abstract: We investigated the changes of pain-related spinal signaling pathway after electroacupuncture (EA) stimulation in a carrageenan-induced rat model. EA stimulation (2Hz, 1mA) was needle-delivered for 30 min at acupoints corresponding to Zusanli and Sanyinjiao 3 h after carrageenan injection. Thermal and mechanical sensitivity of the hindpaw induced by carrageenan was strongly inhibited by EA stimulation. Phosphorylation of extracellular signal-regulated kinase, phosphatidylinositol 3-kinase (PI3K), Akt, and cAMP response element-binding protein (CREB) were examined in the L4-5 segments of the spinal cord by Western blot analysis 4h and 5h after carrageenan injection. Phosphorylation of Akt and especially PI3K were significantly induced by carrageenan-induction, but these expressions were markedly inhibited by EA stimulation. CREB phosphorylation showed a similar, but insignificant, pattern as like PI3k/Akt. Immunohistochemical analyses confirmed that phosphorylation of PI3K and Akt showed a similar pattern as Western blotting and were observed in most neurons and a few astrocytes. EA and PI3K inhibitor synergistically inhibited carrageenan-induced hyperalgesia. These results reveal that both neuronal PI3K and Akt may play an important role in EA-induced antinociception via inactivation in an inflammatory pain model.
authors.affiliation: Division of Meridian and Structural Medicine, School of Korean Medicine, Pusan National University, Yangsan 626-870, Republic of Korea.
authors.forename: Ha Neui
authors.initials: HN
authors.lastname: Kim
authors.forename: Yu Ri
authors.initials: YR
authors.lastname: Kim
authors.forename: Ji Yeon
authors.initials: JY
authors.lastname: Jang
authors.forename: Hwa Kyoung
authors.initials: HK
authors.lastname: Shin
authors.forename: Byung Tae
authors.initials: BT
authors.lastname: Choi
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D050882:CREB-Binding Protein / Q000378:metabolism; D002351:Carrageenan / Q000633:toxicity; D004195:Disease Models, Animal; D015671:Electroacupuncture / Q000379:methods*; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D006930:Hyperalgesia / Q000209:etiology / Q000473:pathology / Q000628:therapy; D007249:Inflammation / Q000139:chemically induced / Q000150:complications / Q000473:pathology / Q000628:therapy*; D008297:Male; D017288:Pain Threshold / Q000187:drug effects / Q000502:physiology; D058539:Phosphatidylinositol 3-Kinase / Q000378:metabolism*; D010751:Phosphopyruvate Hydratase / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects / Q000502:physiology; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000187:drug effects / Q000378:metabolism*; D013997:Time Factors
chemical_list: D002351:Carrageenan; D050882:CREB-Binding Protein; D058539:Phosphatidylinositol 3-Kinase; D051057:Proto-Oncogene Proteins c-akt; D010751:Phosphopyruvate Hydratase