Effects Of Different Frequency Electro-acupuncture On Pain Threshold And Neuronal Nitric Oxide Synthase Contents In Goat Central Nervous System

Nitric oxide (NO) is a kind of small molecules that widespread in body and involved in signal transduction in the nervous system. Its dual role in pain is always discussed by people. The stimulation of electro-acupuncture can cause the change of content in some substances that concerned with the modulation of pain, and nitric oxide is one of these substances. Different animal has different show in the effect of electro-acupuncture's stimulation. It is valuable for us to research how the content of nitric oxide changes in goat central nervous system, which has a good analgesia effect, after stimulation of electro-acupuncture.We review the change of pain threshold after the stimulation of four different frequencies and observe the variation of the neuronal nitric oxide synthase, which is the only nitric oxide synthase in nervous system, to describe the relationship between pain and nitric oxide.35 healthy male goats, weight about 25±2Kg, were randomly divided into 5 groups. They are control group,2Hz group,40Hz group,60Hz group and 100Hz group. Every group has 7 goats. Each goat was measured the pain threshold value on abdominal part before electro-acupuncture, stimulated through "er gen-san yang luo" and "qi jia-bai hui" for 30min, then test the pain threshold value again. Goats were anaesthetized with xylidinothiazoline and perfused by formaldehyde. We remove the brain in 3 min, and mark the nNOS which express in cytoplasm through immunohistochemistry method.The change rate of pain threshold value showed that the average increase rate of 60Hz group goat is 84%, in 40Hz group improved 51%, in 100Hz group improved 54%, and in 2Hz group improved 35%.The result showed that the stimulation of 100Hz can significant increase the expression of nNOS in septal area, amygdaloid nucleus, PAG, nucleus tractus solitarius, supraoptic nucleus, hypothalamic paraventricular necleus, thalamic paraventricular nucleus, nucleus raphe magnus and spinal cord, the stimulation of 2Hz can significant increase the expression in septal area, amygdaloid nucleus, PAG, locus caeruleus, spinal cord, hypothalamic paraventricular necleus and nucleus raphe magnus. The stimulation of 40Hz cans significant increase the expression of nNOS in amygdaloid nucleus, PAG, spinal cord and thalamic paraventricular nucleus. The stimulation of 60Hz only significant increases the expression of nNOS in the thalamic paraventricular nucleus.