Bouazzaoui M, Kannengieser C, Procksch O, Gombos G
Laboratoire de Neurobiologie Cellulaire, UPR 9009 CNRS, Centre de Neurochimie, Strasbourg, France.
Neurochem Res. 1996 Dec;21(12):1527-33. doi: 10.1007/BF02533101.
In this study we show that the glutamate ionotropic agonist kainate (KA) stimulates the efflux of preloaded D-[3H]aspartate (D-[3H]Asp) and inhibits the uptake of this amino acid in cerebellar slices. The effect of this agonist on the efflux of D-[3H]Asp is sensitive to (i) 6-nitro-7-sulphamoylbenzo(f)quinoxaline-2-3-dione (NBQX), indicating the involvement of KA/(RS)-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors, and is (ii) partially tetrodotoxin (TTX)-sensitive, indicating that pre-(TTX-insensitive) and post-synaptic (TTX-sensitive) KA/AMPA receptors are involved. In contrast, the effect on uptake is NBQX- and TTX-insensitive indicating a direct interaction with glutamate transporters. AMPA inhibited D-[3H]Asp uptake and had no effect on D-[3H]Asp efflux. In the same system, the uptake but not the efflux of D-[3H]Asp was affected by dihydrokainate (DHK). The DHK-induced uptake inhibition occurred in the presence of TTX. NBQX inhibited DHK-induced effect at 5 mM but not at 1 mM DHK concentrations.
在本研究中，我们发现离子型谷氨酸受体激动剂红藻氨酸（KA）可刺激预先装载的D-[3H]天冬氨酸（D-[3H]Asp）外流，并抑制小脑切片中该氨基酸的摄取。该激动剂对D-[3H]Asp外流的作用对（i）6-硝基-7-氨磺酰基苯并[f]喹喔啉-2,3-二酮（NBQX）敏感，表明KA/（RS）-α-氨基-3-羟基-5-甲基-4-异恶唑丙酸（AMPA）受体参与其中，并且（ii）对河豚毒素（TTX）部分敏感，表明突触前（TTX不敏感）和突触后（TTX敏感）的KA/AMPA受体均参与其中。相比之下，对摄取的作用对NBQX和TTX不敏感，表明与谷氨酸转运体直接相互作用。AMPA抑制D-[3H]Asp摄取，对D-[3H]Asp外流无影响。在同一系统中，D-[3H]Asp的摄取而非外流受二氢红藻氨酸（DHK）影响。DHK诱导的摄取抑制在TTX存在的情况下发生。NBQX在5 mM时抑制DHK诱导的效应，但在1 mM DHK浓度时则无此作用。
