Extracellular ATP modulates synaptic plasticity induced by activation of metabotropic glutamate receptors in the hippocampus.
Synaptic plasticity is believed to be a cellular mechanism for memory formation in the brain. It has been known that the metabotropic glutamate receptor (mGluR) is required for persistent forms of memory and induction of synaptic plasticity. Application of mGluR agonists induces synaptic plasticity in the absence of electrical conditioning stimulation, such as high or low frequency stimulation. The direction of the mGluR-induced synaptic plasticity, i.e., either long-term potentiation (LTP) or long-term-depression (LTD), is dependent on whether N-methyl-D-aspartate receptors (NMDARs) are co-activated with mGluRs. ATP has modulatory effects on neuronal functions and, in particular, there is increasing evidence that it plays a crucial role in synaptic plasticity. LTP can be induced by application of ATP, and this effect is inhibited by NMDAR antagonist. Although cooperative effects of NMDARs and mGluRs and of NMDARs and extracellular ATP in synaptic plasticity have been revealed, the effect of extracellular ATP on mGluR-induced synaptic plasticity is unknown. In this article, we summarize published data on mGluR- and ATP-induced synaptic plasticity, and present new data showing that extracellular ATP facilitates both the LTP and LTD induced by mGluR activation.
Department of Physiology, Yamagata University School of Medicine.
Yoshihiko
Y
Yamazaki
Satoshi
S
Fujii
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D056547:CA1 Region, Hippocampal / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D004148:Dioxolanes / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects*; D005786:Gene Expression Regulation; D006168:Guinea Pigs; D017774:Long-Term Potentiation / Q000187:drug effects* / Q000502:physiology; D036881:Long-Term Synaptic Depression / Q000187:drug effects* / Q000502:physiology; D008297:Male; D008867:Microtomy; D016202:N-Methylaspartate / Q000494:pharmacology; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D011687:Purines / Q000494:pharmacology; D018094:Receptors, Metabotropic Glutamate; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D013569:Synapses / Q000187:drug effects* / Q000502:physiology; D046509:Tissue Culture Techniques; D014633:Valine / Q000031:analogs & derivatives / Q000494:pharmacology
D004148:Dioxolanes; D011687:Purines; D018094:Receptors, Metabotropic Glutamate; D016194:Receptors, N-Methyl-D-Aspartate; C104068:4-(2-amino-6-chloro-9H-purin-9-yl)-1,3-dioxolane-2-methanol; D016202:N-Methylaspartate; C056639:2-amino-5-phosphopentanoic acid; D000255:Adenosine Triphosphate; D014633:Valine