Akhondzadeh S, Stone T W
Pharmacology Laboratories, University of Glasgow, Scotland, UK.
Brain Res. 1995 Apr 24;677(2):311-8. doi: 10.1016/0006-8993(95)00165-m.
Extracellular recordings were made from the CA1 pyramidal cell layer of hippocampal slices in response to stimulation of Schaffer collateral fibres in stratum radiatum. Alphaxalone and 5 alpha-pregnan-3 alpha-ol-20-one potentiated the inhibitory effect of muscimol on the population spike size at low concentrations (0.5 and 1 microM) that had no significant effect on the spike size by themselves. This profile is in agreement with other reports which have described the effect of these neurosteroids as barbiturate-like. Alphaxalone and 5 alpha-pregnan-3 alpha-ol-20-one also at low concentrations potentiated the inhibitory effect of adenosine alone and in the presence of 1 mM barium which blocked adenosine activated potassium channels. Alphaxalone failed to potentiate the inhibitory effect of adenosine in the presence of 1 microM bicuculline. It is concluded that these neurosteroids enhanced the potentiative interaction between adenosine and muscimol in the presence of barium. The results indicate that adenosine's effects are normally enhanced by virtue of the potentiative interaction occurring with endogenous GABA.
在海马切片的CA1锥体细胞层进行细胞外记录，以响应辐射层中Schaffer侧支纤维的刺激。在低浓度（0.5和1微摩尔）下，alphaxalone和5α-孕烷-3α-醇-20-酮增强了蝇蕈醇对群体峰电位大小的抑制作用，而它们自身对峰电位大小无显著影响。这一情况与其他将这些神经甾体的作用描述为类似巴比妥酸盐的报告一致。在低浓度下，alphaxalone和5α-孕烷-3α-醇-20-酮还增强了单独腺苷以及在存在1毫摩尔钡（其阻断腺苷激活的钾通道）时的抑制作用。在存在1微摩尔荷包牡丹碱的情况下，alphaxalone未能增强腺苷的抑制作用。得出的结论是，在存在钡的情况下，这些神经甾体增强了腺苷与蝇蕈醇之间的增强性相互作用。结果表明，腺苷的作用通常因与内源性γ-氨基丁酸发生增强性相互作用而增强。
