Brown R E, Rabe H, Reymann K G
Department of Neurophysiology, Institute for Neurobiology, Magdeburg, FRG.
Neurosci Lett. 1994 Mar 28;170(1):17-21. doi: 10.1016/0304-3940(94)90228-3.
We have used the selective metabotropic glutamate receptor antagonist (RS)-alpha-methyl-4-carboxyphenylglycine (MCPG) to investigate in the CA1 hippocampal subregion in vitro whether coactivation of N-methyl-D-aspartate (NMDA) and metabotropic glutamate receptors is necessary for the induction of long-term potentiation (LTP) when LTP is induced by theta burst stimulation (TBS). When MCPG (500 microM) was bath applied 14-30 min prior to a triple high-frequency tetanization (100 Hz, 1 s) and washed out immediately afterwards the potentiation of the extracellularly recorded field potentials decayed gradually to baseline (P < 0.05) over 2-3 h. However, when MCPG was applied in the same manner before a triple TBS (10 bursts at 5 Hz, 100 Hz within the bursts) the resulting potentiation remained stable for at least 4 h. MCPG had no effect on baseline synaptic transmission or post-tetanic potentiation. These results demonstrate a clear difference in the mechanisms underlying these two different forms of LTP.
我们使用了选择性代谢型谷氨酸受体拮抗剂（RS）-α-甲基-4-羧基苯基甘氨酸（MCPG），在体外海马CA1亚区研究当通过θ波爆发刺激（TBS）诱导长时程增强（LTP）时，N-甲基-D-天冬氨酸（NMDA）受体和代谢型谷氨酸受体的共同激活对于LTP诱导是否必要。当在三次高频强直刺激（100 Hz，1 s）前14 - 30分钟进行MCPG（500 microM）灌浴给药并随后立即洗脱时，细胞外记录的场电位增强在2 - 3小时内逐渐衰减至基线水平（P < 0.05）。然而，当在三次TBS（5 Hz的10个爆发，爆发内100 Hz）前以相同方式应用MCPG时，所产生的增强至少在4小时内保持稳定。MCPG对基线突触传递或强直后增强无影响。这些结果表明这两种不同形式LTP的潜在机制存在明显差异。
