Fujii T, Baumgärtl H, Lübbers D W
Pflugers Arch. 1982 Mar;393(1):83-7. doi: 10.1007/BF00582396.
The relationship between tissue oxygen partial pressure (pO2) values and electrical activities of guinea pig olfactory cortical slices were investigated as the slices were superfused with Krebs-Ringer's solution equilibrated with different gas mixtures. The pO2 values were measured in the slices with oxygen microelectrodes (tip diameter less than 1 micrometer). 1. Studies of pO2 measurements showed the variability of minimum pO2 value of oxygen profiles in the tissue slice. The profile depends on the pO2 value of the superfusate and on the thickness and the oxygen consumption of the slice. With our experimental conditions an anoxic area developed in the middle layers of the slice when the thickness of the slice exceeded ca. 430 micrometers; in thinner slices there was no anoxic area. In our case the limiting section thickness of the slice was ca.430 micrometers from the viewpoint of tissue pO2 value. 2. The N potential (extra-cellularly recorded EPSP) showed a tendency to decrease in amplitude, for slices being thicker than ca 430 micrometers. It would seem reasonable to think that the decrement of the N potential was brought about by the existence of the anoxic area. 3. When the slice was bubbled with 25, 45 or 95% O2, the tissue pO2 value changed, and the N potential height also changed. The N potential was higher in amplitude when bubbled with 95% O2 than with 25% O2. On the other hand, the amplitude of the IS potential (the lateral olfactory tract potential) was not influenced as much as that of the N potential by the change of tissue pO2 value in the slice. 4. The tissue pO2 value was continuously measured during the electrical stimulation of the lateral olfactory tract. The steady state level of tissue pO2 value obtained during the stimulation diminished as the frequency of stimulation increased from 5-30 Hz.
当用不同气体混合物平衡的 Krebs-Ringer 溶液对豚鼠嗅觉皮质切片进行灌流时，研究了组织氧分压（pO₂）值与电活动之间的关系。用氧微电极（尖端直径小于 1 微米）测量切片中的 pO₂值。1. pO₂测量研究表明，组织切片中氧分布的最低 pO₂值存在变异性。该分布取决于灌流液的 pO₂值、切片的厚度和氧消耗。在我们的实验条件下，当切片厚度超过约 430 微米时，切片中层会出现缺氧区域；在较薄的切片中则没有缺氧区域。就组织 pO₂值而言，在我们的实验中，切片的极限厚度约为 430 微米。2. 对于厚度超过约 430 微米的切片，N 电位（细胞外记录的兴奋性突触后电位）的幅度有减小的趋势。认为 N 电位的减小是由缺氧区域的存在导致的，这似乎是合理的。3. 当用 25%、45%或 95%的 O₂对切片进行通气时，组织 pO₂值发生变化，N 电位高度也发生变化。用 95%的 O₂通气时 N 电位的幅度高于用 25%的 O₂通气时。另一方面，切片中组织 pO₂值的变化对 IS 电位（外侧嗅束电位）幅度的影响不如对 N 电位的影响大。4. 在对外侧嗅束进行电刺激期间持续测量组织 pO₂值。随着刺激频率从 5 - 30 Hz 增加，刺激期间获得的组织 pO₂值的稳态水平降低。
