Hildesheimer M, Rubinstein M, Nuttal A L, Lawrence M
Hear Res. 1982 Oct;8(2):187-98. doi: 10.1016/0378-5955(82)90074-0.
Impairment of the cochlear blood supply of guinea pigs was induced in order to study the effects of hypoxia on the cochlear action potentials. The oxygenation of the cochlear structures was decreased by perfusing the ears with polycythemic hyperviscous blood. The validity of using this model of cochlear blood flow was based on the propensity of the blood to flow in a laminar way. Because of the streamlined flow pattern, the blood supplied by the two vertebral arteries does not mix within the common trunk of the basilar artery. The retrograde injection of polycythemic hyperviscous blood into one vertebral artery will affect the ear on the injected side only. The high viscosity of the polycythemic blood decreases the rate of flow of blood through the cochlear vessels; the high oxygen content of this blood, however, avoids hypoxia of the cochlea. Therefore, in order to make the slowdown in the blood flow evident, its oxygen content was reduced to a 'precritical level' before it was infused. Injecting normoviscous blood with a 'precritical level' of oxygen caused a mild reduction in the scala media pO2 of 15.2% for the whole group of twenty animals. The hyperviscous blood with the same level of oxygenation, however, reduced the pO2 in the scala media to 53.3% of normal. These findings explain the difference in the altered click-evoked action potentials in the two groups of animals.
为了研究缺氧对豚鼠耳蜗动作电位的影响，诱导其耳蜗血液供应受损。通过用红细胞增多症高粘滞血液灌注耳朵来降低耳蜗结构的氧合。使用这种耳蜗血流模型的有效性基于血液以层流方式流动的倾向。由于流线型流动模式，两条椎动脉供应的血液在基底动脉的共同主干内不会混合。将红细胞增多症高粘滞血液逆行注入一条椎动脉只会影响注射侧的耳朵。红细胞增多症血液的高粘度降低了通过耳蜗血管的血流速度；然而，这种血液的高氧含量可避免耳蜗缺氧。因此，为了使血流减慢明显，在注入之前将其氧含量降低到“临界前水平”。给20只动物的整个群体注射氧含量处于“临界前水平”的正常粘度血液，导致蜗管中pO2轻度降低15.2%。然而，相同氧合水平的高粘滞血液将蜗管中的pO2降低到正常的53.3%。这些发现解释了两组动物中改变的短声诱发动作电位的差异。
