Group I metabotropic glutamate receptors are involved in TEA-induced long-term potentiation at mossy fiber-CA3 synapses in the rat hippocampus.
Gq-protein-coupled Group I metabotropic glutamate receptors (mGluR) reportedly activate phospholipase C (PLC), leading to Ca(2+) release from intracellular stores and the formation of diacylglycerol (DAG). We electrophysiologically examined the involvement of the Group I mGluR in tetraethylammonium (TEA)-induced long-term potentiation (LTP) at mossy fiber (MF)-CA3 synapses in the rat hippocampus. TEA-induced LTP was almost completely blocked under the selective blockade of either mGluR1 or mGluR5, both of which are Group I mGluR. This result was supported by the blockade of TEA-induced LTP even in the absence of these blockers under low temperature conditions, in which the activation of Group I mGluR is thought not to be fully effective. In addition, the blockade of mGluR1 resulted in lower short-term potentiation (STP) during TEA application compared with the blockade of mGluR5. These results demonstrate the crucial roles of Group I mGluR in the TEA-induced LTP at MF-CA3 synapses and the different contributions of mGluR1 and mGluR5 to the initial component of plasticity.
Suzuki
Etsuko
E
Department of Psychology, Faculty of Human Sciences, Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo 102-8554, Japan.
Okada
Takashi
T
D000818:Animals; D056654:CA3 Region, Hippocampal / Q000187:drug effects* / Q000502:physiology; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology; D066298:In Vitro Techniques; D017774:Long-Term Potentiation / Q000187:drug effects* / Q000502:physiology; D008297:Male; D009473:Neuronal Plasticity / Q000187:drug effects / Q000502:physiology; D009474:Neurons / Q000187:drug effects* / Q000502:physiology; D026902:Potassium Channel Blockers / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D064529:Receptor, Metabotropic Glutamate 5; D018094:Receptors, Metabotropic Glutamate / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013569:Synapses / Q000187:drug effects / Q000502:physiology; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology; D013696:Temperature; D019789:Tetraethylammonium / Q000494:pharmacology*; D013997:Time Factors
C578935:GRM5 protein, human; C578937:Grm5 protein, rat; D026902:Potassium Channel Blockers; D064529:Receptor, Metabotropic Glutamate 5; D018094:Receptors, Metabotropic Glutamate; C104077:metabotropic glutamate receptor type 1; D019789:Tetraethylammonium