• Ha Neui Kim, Yu Ri Kim, Ji Yeon Jang, Hwa Kyoung Shin, and Byung Tae Choi.
• Division of Meridian and Structural Medicine, School of Korean Medicine, Pusan National University, Yangsan 626-870, Republic of Korea.
• Brain Res. Bull. 2012 Feb 10;87(2-3):199-204.

AbstractWe 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.Copyright © 2011 Elsevier Inc. All rights reserved.

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