Sato Y, Aoki M
Department of Physiology, Sapporo Medical University School of Medicine, Japan.
Neurosci Lett. 1997 Feb 28;223(3):181-4. doi: 10.1016/s0304-3940(97)13439-5.
The effects of midazolam, one of the most popular benzodiazepines, was examined on excitatory synaptic transmission in the hippocampus. Both CA1 pyramidal cells (CA1-PCs) and dentate gyrus granule cells (DG-GCs) were studied in rat hippocampal slices with extracellular recordings. Midazolam depressed the amplitudes of orthodromic population spikes (O-PS) and excitatory postsynaptic potential (EPSP) slopes of CA1-PCs in a dose-dependent manner, but depressed those of DG-GCs to a lesser extent. On the other hand, midazolam had little effect on the amplitudes of antidromic population spikes of both CA1-PCs and DG-GCs. A GABAA receptor antagonist bicuculline strongly antagonized the depressant effects of 75 microM midazolam on the amplitudes of O-PS by 73% in CA1-PCs, whereas it did not antagonize the effects of midazolam in DG-GCs. These results suggest that the differential effects of midazolam could be due to the different types and/or density of GABAA receptors between CA1-PCs and DG-GCs.
研究了最常用的苯二氮䓬类药物之一咪达唑仑对海马体兴奋性突触传递的影响。采用细胞外记录法，在大鼠海马体切片中对CA1锥体细胞（CA1-PCs）和齿状回颗粒细胞（DG-GCs）进行了研究。咪达唑仑以剂量依赖性方式降低了CA1-PCs的顺向群体峰电位（O-PS）幅度和兴奋性突触后电位（EPSP）斜率，但对DG-GCs的降低程度较小。另一方面，咪达唑仑对CA1-PCs和DG-GCs的逆向群体峰电位幅度几乎没有影响。GABAA受体拮抗剂荷包牡丹碱强烈拮抗75微摩尔咪达唑仑对CA1-PCs中O-PS幅度的抑制作用，拮抗率达73%，而在DG-GCs中它不拮抗咪达唑仑的作用。这些结果表明，咪达唑仑的不同作用可能是由于CA1-PCs和DG-GCs之间GABAA受体的类型和/或密度不同所致。
