低氧对家兔局部脑血循环及脑组织中血管活性肠肽含量的影响

本实验观察了急性低氧及低氧习服家兔暴露于模拟海拔5000米低氧环境时局部脑血流量变化及脑组织中血管活性肠肽(简称VIP)含量变化。动物分为急性低氧组,低氧习服组和常压对照组。用脑电阻图法测定了家兔大脑皮层、下丘脑和海马三个部位的血流变化,用放射免疫分析法测定了以上部位组织中VIP的含量变化。结果表明,急性低氧可引起局部脑血流量增加,其幅度为42.6%～78.8%(P<0.05),但低氧习服动物三个部位血流量均无显著变化。急性低氧组脑组织VIP含量较对照有明显增加,大脑皮层VIP含量自对照107.9±8.3ng/s组织增至120.8±16.9ns/g组织,下丘脑自12.1±1.1ng/g组织增至21.1±2.9ng/g组织(P<0.05),海马VIP含量自对照的35.7±2.6ng/gTiss增至45.9±1.7ng/g组织(P<0.01),低氧习服组的VIP含量无显著变化。本实验结果提示,急性低氧可引起家兔脑组织中VIP含量增加,这一变化很有可能参与低氧时脑血流量的调节过程。

The change of regional cerebral blood flow (rCBF) and the brain tissue concentration of vasoactive intestinal peptide (VIP) in rabbits during exposured to hypoxia

In this cxperiment, we observed the changes of regional cerebral blood flow (rCBF) and the brain tissue concentration of vasoactive intestinal peptide(VIP) in rabbits during exposured to a simulated altitude of 5000m. The animals were derided into acute hypoxic, hypoxic acclimatized and normoxic control groups. Rheoencephalongraphy method was employed to record the changes of rCBF in cortex (Cort), hypothalamus (HTL) and hippocampus (HPC) and the VIP concentration of the same areas was studied with radioimmunoassay method. The results showed that the rCBF of the areas recorded was increased by 42.6-78.8%(P<0.05) in acute hypoxie gropup, but no obvious change was found in the hypoxic acclimatized group. The tissue concentration of VIP increased obviously in acute hypoxic group: in Cort, HTL and HPC, the concentration of VIP increased by 11.9%74.4 (P<0.05) and 28.3%(P<0.01) respectively. While, there were no significant change found in hypoxic acclimatized group. We concluded that exposure to acute hypoxia could enhance the VIP concentration of the brain tissue and this change may play an important role in the increment of CBF during hypoxia.