Manzoni O J, Weisskopf M G, Nicoll R A
Department of Pharmacology, University of California at San Francisco 94143-0450.
Eur J Neurosci. 1994 Jun 1;6(6):1050-4. doi: 10.1111/j.1460-9568.1994.tb00599.x.
In the CA1 and CA3 regions of the guinea pig hippocampus, we have tested the ability of the new antagonist (RS)-alpha-methyl-4-carboxyphenylglycine (MCPG) to inhibit the well-known effects of (trans)-1-amino-cyclopentyl-1,3-dicarboxylate (ACPD), a specific agonist of glutamate metabotropic receptors. Whole-cell recordings showed that MCPG was able to antagonize the blocking action of ACPD on IAHP in the CA1 region. In addition, we report here that MCPG also antagonized the presynaptic inhibitory actions of ACPD on field excitatory postsynaptic potentials in both areas CA1 and CA3. Thus, MCPG proved to be an effective tool for determining physiological roles of the glutamate metabotropic receptors in synaptic transmission in the hippocampus. We next tested the possible effects of this antagonist on long-term potentiation (LTP). In completely blind experiments MCPG was without effect on LTP in both areas CA1 and CA3. In conclusion, our results suggest that, although MCPG is a valuable antagonist of the ACPD-sensitive receptors, it has no inhibitory effect on LTP.
在豚鼠海马体的CA1和CA3区域，我们测试了新型拮抗剂（RS）-α-甲基-4-羧基苯甘氨酸（MCPG）抑制（反式）-1-氨基环戊基-1,3-二羧酸（ACPD）（一种谷氨酸代谢型受体的特异性激动剂）的已知作用的能力。全细胞记录显示，MCPG能够拮抗ACPD对CA1区域IAHP的阻断作用。此外，我们在此报告，MCPG还能拮抗ACPD对CA1和CA3区域场兴奋性突触后电位的突触前抑制作用。因此，MCPG被证明是确定谷氨酸代谢型受体在海马体突触传递中的生理作用的有效工具。接下来，我们测试了这种拮抗剂对长时程增强（LTP）的可能影响。在完全盲法实验中，MCPG对CA1和CA3区域的LTP均无影响。总之，我们的结果表明，尽管MCPG是ACPD敏感受体的一种有价值的拮抗剂，但它对LTP没有抑制作用。
