【摘要】 以乌拉坦麻醉兔,给予静脉注射去甲肾上腺素,观察在血压升高的同时,动物的呼吸和在延髓腹侧蛛网膜下腔记录的颅内压变化。结果完整动物血压升高时,潮气量明显减小,而颅内压保持相对稳定。切断双侧颈动脉窦神经和减压神经的动物,注药使血压升高时,仍可见潮气量明显减小,颅内压的增值较完整动物大。电灼损毁双侧延髓腹外侧区后,静脉注射去甲肾上腺素使血压上升时,颅内压增值明显高于其他两组(与完整动物组相比p<0.01,与切断双侧颈动脉窦神经相比p<0.05)。颅内压升高的时程和形式与外周血压的变化相一致。结果表明,在脑灌流压(量)增加时,延髓膜外侧区的功能完整性对保持颅内压相对稳定具有重要作用。更多还原

【Abstract】 An area of the ventral medulla supplied by vertebral arterial blood was sensitive to local pressure and/or cerebral perfusion pressure was recently reported by us. An increase in pressure of either would cause diminution in ventilation tida volume (VT) and lowering of blood pressure (BP). The present study was carried out on urethane anesthetized rabbits. The intraoranial pressure (IOP) of the ventral medulla region was measured and recorded directly through the subaraohnoid space-Norepinephrine (NE) 0.2mg/ml was injected intravenously to observe the variations of ventilation and IOP during elevation of BP. The results revealed: (1) In intact animals (n=6), despite an increase in BP (△BP) by 9.31-13.57 or 11.97 ±0.64kPa(M±SD) and a decreased response of VT (△VT 27.5±3.7ml) after NE Injection, ICP was raised only 0.066-0.82 or 0.16±0.03kPa. (2) In bilateraly sinoaortio denervated and vagotomized animals, exaggerated fluctuations in BP and ICP could be observed. An increase in JBP of 7.32 -13.70 or 11.4±0.98kPa could cause reduction of VT (△VT 36.5± 2.22ml), and elevation of IOP (△ICP 0.24-0.53 or 0.32±0.06kPa). (3) Electroaoagulation of bilateral barosensitive areas at the ventral medulla was accomplished in 6 rabbits. Apnea occurred in 4 of them, artificial ventilation was given in time to maintain animals’ lives. When an increased △BP of 8.65-15.30 or 10.97±0.86 kPa was induced by NE injection, one of the animals with spontaneous breathing developed Inhibition of respiration as usual, but another one showed an increase in VT (from 20 to 40ml). All animals in this group showed remarkable elevation of ICP, the △ICP was up to 0.80-2.00 or 1.15-0.16kPa. The time course and pattern of ICP changes were similar to those of BP changes. It is concluded that the barosensitive area at the veatral medulla may play an important role in maintaining stability of ICP whenever an increase in cerebral blood flow or perfusion pressure occurred.更多还原