Southan A P, Wann K T
Division of Anaesthesia, Clinical Research Centre, Harrow, Middlesex, UK.
Eur J Neurosci. 1996 Dec;8(12):2571-81. doi: 10.1111/j.1460-9568.1996.tb01551.x.
We have investigated the effects of high helium pressure (up to 13.3 MPa) on the electrophysiological responses of CA1 neurons in rat hippocampal slices using a purpose built pressure chamber, designed to facilitate field potential and intracellular recording. In field potential experiments, near threshold orthodromic responses were depressed by modest pressure (0.4 MPa). At higher stimulus intensities, orthodromic and antidromic population spike amplitudes were not increased at 5 MPa but were significantly enhanced at 10 MPa, and multiple population spikes were observed in some experiments. Orthodromic paired pulse potentiation was not affected by pressure up to 10 MPa. In intracellular experiments there were no significant differences between mean values obtained for resting membrane potential and input resistance at atmospheric pressure and pressures of up to 10 MPa. However, spontaneous depolarizing membrane potential excursions, decreased slow after-hyperpolarization responses and reduced accommodation properties were observed at pressure (5-10 MPa). One possibility is that the SK and M potassium channel systems may be more sensitive to high pressure than other membrane ion channels. These effects may contribute towards the high pressure neurological syndrome observed in vivo.
我们使用专门设计的压力室，研究了高氦气压力（高达13.3兆帕）对大鼠海马切片中CA1神经元电生理反应的影响，该压力室旨在便于进行场电位和细胞内记录。在场电位实验中，适度压力（0.4兆帕）会抑制接近阈值的顺向反应。在较高刺激强度下，5兆帕时顺向和逆向群体峰电位幅度未增加，但在10兆帕时显著增强，并且在一些实验中观察到多个群体峰电位。高达10兆帕的压力对顺向配对脉冲增强无影响。在细胞内实验中，大气压和高达10兆帕压力下获得的静息膜电位和输入电阻平均值之间无显著差异。然而，在5 - 10兆帕压力下观察到自发去极化膜电位偏移、缓慢后超极化反应减弱和适应性特性降低。一种可能性是，SK和M钾通道系统可能比其他膜离子通道对高压更敏感。这些效应可能导致体内观察到的高压神经综合征。
