[Role of adenosine in weak electro-acupuncture-induced depression of nociceptive response of spinal dorsal horn neurons in rats].

In this study, extracellular recordings were made from wide dynamic range (WDR) neurons in lumbar segments of the spinal cord in rats transsected at the first lumbar segment. The nociceptive discharges of WDR neurons were depressed by weak electro-acupuncture applied to "Yanglingquan"-"Xuanzhong" points. The depression was blocked by i.v. administration of adenosine receptor antagonists, theophylline and caffeine. The observations indicate that depression of the nociceptive response of the WDR neurons induced by weak EA may be mediated by adenosine within the spinal cord.