The Effects of 120Hz Electroacupuncture on the Prostaglandin E2 and Spinal N-Methyl-D-Aspartate Receptor Expression in the Carrageenan-Injected Rat

고빈도 120 Hz 전침이 Carrageenan으로 유발된 흰쥐의 Prostaglandin E2와 척수 N-Methyl-D-Aspartate Receptor 발현에 미치는 영향

Objective : The role of high frequency 120 Hz electroacupuncture(EA) in carrageenan-induced pain was studied by examining the alnalgesic effects, and prostaglandin $E_2(PGE_2)$ levels measurement and spinal N-methyl-D-aspartate(NMDA) receptor expression. Inflammation was induced by an intraplantar injection of 1% carrageenan into the right hind paw. Method : Bilateral EA stimulation with 120 Hz were delivered at those acupoints corresponding to Zusanli and Sanyinjiao in man via the needles for a total of 30 min duration in carrageenan-injected rats. Results : EA stimulation showed significant analgesic effects as measured by analgesy-meter at all time points tested compared with controls. Three hours after carrageenan injection, PGE2 levels were measured by commercial kit. EA significantly inhibited PGE2 production in the right paw. The number of NR1 and NR2A, NMDA receptor, immunoreactive neurons was significantly increased in the superficial dorsal horn(laminae I-II) and nucleus proprius(laminae III-IV) of ipsilateral spinal cord at L4-5. But the number of carrageenan-induced NR1 and NR2A immunoreactive neuron, especially NR1 immunoreaction in the superficial dorsal horn, was reduced by 120 Hz EA stimulation. Conclusions : These results indicate that NMDA receptors may mediate transmission of nociceptive information originating in tissue inflammation of hind paw and high frequency 120 Hz EA stimulation have an alleviating action against local inflammatory pain.