Popova E
Department of Physiology, Medico-Biological Institute, Medical Academy, Sofia, Bulgaria.
Physiol Bohemoslov. 1989;38(4):327-37.
The effect of blockade of GABAergic synapses by picrotoxin on the b- and d-wave of frog ERG was investigated under scotopic (0.002 lx), mesopic (2 lx) and photopic (200 lx) background illumination (Ib). Diffuse white stimuli with two levels of contrast (0.5 and 2.5) were used with each Ib. The aim was to compare the effects of picrotoxin at different background levels, but same stimulus contrast. We found that picrotoxin markedly increased the amplitude and rate of rise of the leading edge of the b- and d-wave with each Ib. This effect was most pronounced at mesopic Ib, smaller at photopic Ib and least pronounced at scotopic Ib. It was relatively stronger on the d-wave than on the b-wave amplitude under scotopic and mesopic conditions. Under photopic conditions, the difference between the picrotoxin effect on the b- and d-wave was much smaller. The possible neuronal mechanisms of the above described picrotoxin effects are discussed.
研究了在暗视（0.002勒克斯）、中间视觉（2勒克斯）和明视（200勒克斯）背景光照（Ib）条件下，苦味毒阻断γ-氨基丁酸能突触对青蛙视网膜电图b波和d波的影响。在每种Ib条件下，使用具有两种对比度水平（0.5和2.5）的漫射白色刺激。目的是比较不同背景水平但相同刺激对比度下苦味毒的作用。我们发现，在每种Ib条件下，苦味毒均显著增加了b波和d波前沿的幅度和上升速率。这种效应在中间视觉Ib条件下最为明显，在明视Ib条件下较小，在暗视Ib条件下最不明显。在暗视和中间视觉条件下，其对d波的作用相对比对b波幅度的作用更强。在明视条件下，苦味毒对b波和d波的作用差异要小得多。文中讨论了上述苦味毒作用可能的神经元机制。
