阻断猫基底动脉引起的延髓缺血和呼吸血压效应的研究

EFFECTS OF MEDULLARY ISCHEMIA ON RESPIRATORY AND BLOOD PRESSURE INDUCED BY LIGATING BASILAR ARTERY IN CAT

目的 :通过结扎基底动脉主干不同节段观察脑干缺血范围和神经元形态学变化以及呼吸活动和动脉血压的变化 ,为进一步探讨脑干缺血影响呼吸和循环等功能活动的机制和防治措施提供依据。方法 :以猫为实验对象 ,结扎基底动脉主干不同节段 ,分析脑干缺血区血管密度和神经元形态学变化 ,以膈肌肌电和股动脉血压为指标 ,观察呼吸活动和血压的变化。结果 :结扎基底动脉可引起延髓血管密度减小 ,引起延髓缺血。结扎基底动脉不同节段引起的缺血范围有明显重叠 ,缺血区主要位于闩平面吻端的延髓。缺血区神经元胞体肿胀 ,尼氏染色着色变浅 ,尼氏体减少。动物的吸气时程 (TI)和呼气时程 (TE)缩短 ,呼吸频率 (RF)增快 ,平均动脉血压 (MBP)下降 ,均P <0 .0 5,呼吸幅度 (A)无明显变化。结论 :基底动脉不同节段对延髓的血液供应有明显重叠 ,延髓缺血可引起呼吸和血压改变 ,延髓缺血性神经元损伤是引起呼吸。

Aim: Observations on medullary ischemia region, the morphology of neuron s and changes of respiration and blood pressure were made, in order to give evid ences on how medullary ischemia affects respiration and circulation and give som e advices on how to protect from it. Methods: Using cats as the experimental animals, the different parts of the basilar artery trunk were ligat ed. The changes in the density of blood vessels, the morphology of neurons in th e brainstem, the electromyogram (EMG) of the diaphragm and the blood pressure of the femoral artery were investigated. Results: The density of blood vessels notably decreased in the medulla after ligating the basilar artery trunk. The ischemic range induced by ligation of the different parts of the bas ilar artery trunk overlapped, mainly locating in the medulla rostral to the obex . The soma were swelled and the Nissl bodies decreased in some of neurons in th e ischemic region of medulla. The duration of inspiration (T I) and expiration (T E) shortened, respiratory frequency (RF) increased, and mean blood pressure (MBP) decreased in the experimental groups (P<0.05). Conclusion: There is an obvious overlap of the areas in which blood supplied by different parts of the basilar artery trunk. Medullary ischemia can involve in changes of respiration and blood pressure. The ischemic damage of neurons in the medulla m ight be the structural basis of the changes in the respiratory and circulatory f unctions.