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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。
In this study, we observed the change of local cerebral blood flow and the content of vasoactive intestinal peptide (VIP) in acute hypoxic and hypoxic habitat rabbits exposed to hypoxia environment of simulated altitude 5000 m. Animals were divided into acute hypoxic group, hypoxic preconditioning group and normobaric control group. The changes of blood flow in three parts of rabbit cerebral cortex, hypothalamus and hippocampus were measured by using brain resistance graph. The contents of VIP in the above tissues were determined by radioimmunoassay. The results showed that acute hypoxia caused local cerebral blood flow increased, ranging from 42.6% to 78.8% (P <0.05), but no significant changes in blood flow in all three hypoxic-exposed animals. The content of VIP in brain tissue of acute hypoxia group was significantly increased compared with control group. The content of VIP in cerebral cortex increased from 107.9 ± 8.3ng / s to 120.8 ± 16.9ns / g in control group, and from 12.1 ± 1.1ng / g in hypothalamus to 21.1 (P <0.05). The content of VIP in the hippocampus increased from 35.7 ± 2.6 ng / g Tiss in the control group to 45.9 ± 1.7 ng / g tissue (P <0.01), and there was no significant change in the VIP level . The results suggest that acute hypoxia can cause increased brain VIP content in rabbits, this change is likely to participate in the regulation of cerebral blood flow during hypoxia.