纳洛酮和阿托品翻转电针抑制关节炎大鼠束旁核神经元伤害性反应的作用

REVERSAL OF THE INHIBITORY EFFECT OF ELECTROACUPUNCTURE ON THE NOCICEPTIVE RESPONSE OF NEURONS IN PARAFASCICULAR NUCLEUS BY NALOXONE AND ATROPINE IN ACUTE ARTHRITIC RATS

用急性佐剂性关节炎大鼠作为病理性疼痛的实验模型，以丘脑束旁核中对伤害性刺激发生兴奋反应的单位放电作为指标，观察电针的影响，并分析其机制。实验发现电针能明显抑制伤害性反应；脑室注射阿片受体阻断剂纳洛酮（４μｇ／１０μｌ）或Ｍ受体阻断剂阿托品（５μｇ／１０μｌ）均能翻转电针的这种抑制作用。实验还发现脑室注射纳洛酮或阿托品对关节炎大鼠束旁核神经元自发放电有增频作用。实验结果提示：电针对关节炎大鼠丘脑束旁核神经元伤害性反应的抑制，可能是通过脑内阿片系统和胆碱能系统而发挥作用的；这两个系统对关节炎大鼠丘脑束旁核神经元自发放电可能有紧张性抑制作用。

Rats with adjuvant arthritis were used as an animal model of pathological pain in this experiment and the nociceptive response of neurons in parafascicular nucleus (Pf)were recorded and intracerebroventricular(icv) injection of naloxone and atropine was adopted in order to investigate the effect of elcetroacupuncture (EA) and to analyze the neurotransmitters involved. The main results were as follows: (1) The nociceptive response of the majority of Pf neurons (29/34) in arthritic rats was significantly inhibited by EA at acupoints of "Zusanli" and "Sanyinjiao"; (2) The inhibitory effect of EA was reversed in 12/13 units by icv injection of naloxone (4 μg/ 10 μl);(3) The inhibitory effect of EA was also reversed in 11/12 units by icv injection of atropine (5μg/10μl) (4) The spontaneous unit discharge of Pf neurons in arthritic rats was increased after icv injection of naloxone or atropine.Experimental results suggest that EA could have an inhibitory effect on the nociceptive response of Pf neurons in arthritic rats, which might be mediated by opioid system and cholinergic system in the brain, and that opioid system and cholinergic system might have a tonic inhibitory effect on the spontaneous unit dicharge of Pf neurons in arthritic rats.