家兔孤束核区微量注射羟基马桑毒素对该区神经组织的形态学影响

Effects of Microinjection of Tutin into Nucleus Tractus Solitarius Region on the Morphology of Neural Tissue of this Area in Rabbit

用经乌拉坦麻醉、肌肉麻痹、切断双侧颈迷走神经的8只日本大耳白兔,于一侧孤束核区微量注射(10μg/μl)羟基马桑毒素后4小时,光镜下(n=5)见注射区部分神经元胞体尼氏体溶解,核嗜碱性增加,神经毡空隙增大呈“海绵状”。尼氏体溶解的神经元与正常神经元混杂分布。电镜下(n=3)见上述神经元胞体中粗面内质网池异常扩张,核异染色质明显增加;神经毡中部分神经胶质成分水肿,树突变空。偶见轴突肿胀。对照侧神经元及神经毡的结构无明显改变。提示:羟基马桑毒素破坏某些神经元的胞体-树突,可能有兴奋性毒性作用。

Four hours after unilateralmicroinjection of tutin(10μg)into the NTSregion, the nervous tissue surrounding thecenter of microinjection showed the fol-lowing morphologic changes:1.Under thelight microscopic examination(n=5), theneuronal body showed chromatolysis andthe nuclear basophilia enhanced in about17% of the neurons; the lacunae of neu-ropil distended and gave a 'spongy' ap-pearance. The neurons with lesion mingledwith the normal ones in the absence of dis-tinct demarcation. 2. Under the electronmicroscopic examination(n=3), the cisterns of rough endoplasmic raticulum dis-tended, and the nuclear electron densityincreased on account of the increased nu-clear chromatin in the affected cells. Theorganelles of dendrites decreased or disap-peared;the neuroglia looked edematous.There were only a few axons which lookededematous in the neuropil. Microinjection of the same volume(1μl)of NS into the other side of NTS region in the same rabbit didn't show any sign ofdamage as those described above. Thus,our preliminary results suggest that tutinmight damage the soma and dendrites ofsome neurons, and therefore, it might bea neuroexcitotoxin.