乙酰胆碱、阿托品、毛果芸香碱在痛觉调制中对大鼠蓝斑核神经元形态的影响

目的 研究乙酰胆碱(ACh)、阿托品、毛果芸香碱与正常大鼠蓝斑核(LC)在痛觉调制中的作用及其相互关系.方法 采用电生理学与侧脑室给药的方法,以电脉冲刺激坐骨神经作为伤害性刺激,用玻璃微电极引导LC中痛反应神经元的电变化.观察ACh、阿托品、毛果芸香碱对LC中神经元形态学改变的影响.结果 ACh可使LC内神经元形态发生改变,即神经元体积变大、外形不规则,细胞核轻度水肿等.M受体拮抗剂阿托品能阻断上述作用,使神经元结构基本恢复正常.M受体激动剂毛果芸香碱能产生与ACh相似的效应.结论 外源性ACh不仅能加强大鼠LC中痛反应神经元的电活动,而且使神经元的形态也发生了相应的改变,表现为易化疼痛效应.揭示,ACh的易化疼痛作用主要是通过M受体介导而实现的,LC内神经元形态的改变进一步证实ACh和LC在痛觉调制中起重要作用.

Influence of acetylcholine, atropine, and pilocarpine on the morphologies of neurons in locus ceruleus of rats in the algesic modulation

Objective To study the role and the interaction between drugs of acetylcholine(ACh),atropine,and pilocarpine and locus ceruleus(LC) of normal rats in the algesic modulation.Methods The electrophysiological method and intracerebroventricular injection of medical method were used in the experiment.The sciatic nerve was stimulated by train of electrical impulses as noxious stimuli.The electric changes of pain-related neurons in LC was led out by the glass microelectrode.The morphological changes of neurons in LC by the influence of ACh,atropine,and pilocarpine were observed in the end of the experiment.Results The morphological changes of neurons in LC were caused by the ACh,i.e.the neuronal volumes fill out,the neuronal externality was irregular,and the neuronal nucleus was swelling,etc.The M receptor antagonist atropine could block the effects of ACh,and the morphological changes of neurons in LC gradually recovered the normal.The M receptor agonist pilocarpine was similar to the effects of ACh.Conclusion The exogenous ACh not only strengthen the electrical activities of pain-related neurons but cause the morphological changes of neurons in LC of rats,exhibiting the effect of facilitated pain.It is exposed that the facilitated painful effects of ACh realized by the M receptor.The morphological changes of neurons in LC further demonstrate that the ACh and LC play a very important role in the modulation of algesia.