Kogo Takamiya

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Plasticity of the nervous system is dependent on mechanisms that regulate the strength of synaptic transmission. Excitatory synapses in the brain undergo long-term potentiation (LTP) and long-term depression (LTD), cellular models of learning and memory. Protein phosphorylation is required for the induction of many forms of synaptic plasticity, including(More)
Emotion enhances our ability to form vivid memories of even trivial events. Norepinephrine (NE), a neuromodulator released during emotional arousal, plays a central role in the emotional regulation of memory. However, the underlying molecular mechanism remains elusive. Toward this aim, we have examined the role of NE in contextual memory formation and in(More)
Near coincidental pre- and postsynaptic action potentials induce associative long-term potentiation (LTP) or long-term depression (LTD), depending on the order of their timing. Here, we show that in visual cortex the rules of this spike-timing-dependent plasticity are not rigid, but shaped by neuromodulator receptors coupled to adenylyl cyclase (AC) and(More)
PSD-95 is a major protein found in virtually all mature excitatory glutamatergic synapses in the brain. Here, we have addressed the role of PSD-95 in controlling glutamatergic synapse function by generating and characterizing a PSD-95 KO mouse. We found that the alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)subtype of glutamate receptor(More)
The insertion of AMPA receptors (AMPARs) into the plasma membrane is an important step in the synaptic delivery of AMPARs during the expression of synaptic plasticity. However, the molecular mechanisms regulating AMPAR insertion remain elusive. By directly visualizing individual insertion events of the AMPAR subunit GluR1 in rodents, we found that the(More)
Synaptic GTPase-activating protein (SynGAP) is a neuronal RasGAP (Ras GTPase-activating protein) that is selectively expressed in brain and highly enriched at excitatory synapses, where it negatively regulates Ras activity and its downstream signaling pathways. To investigate the physiological role of SynGAP in the brain, we have generated mutant mice(More)
Cerebellar long-term depression (LTD) is a major form of synaptic plasticity that is thought to be critical for certain types of motor learning. Phosphorylation of the AMPA receptor subunit GluR2 on serine-880 as well as interaction of GluR2 with PICK1 have been suggested to contribute to the endocytic removal of postsynaptic AMPA receptors during LTD.(More)
A recently described form of synaptic plasticity results in dynamic changes in the calcium permeability of synaptic AMPA receptors. Since the AMPA receptor GluR2 subunit confers calcium permeability, this plasticity is thought to occur through the dynamic exchange of synaptic GluR2-lacking and GluR2-containing receptors. To investigate the molecular(More)
Gangliosides, sialic acid-containing glycosphingolipids, are abundant in the vertebrate (mammalian) nervous system. Their composition is spatially and developmentally regulated, and gangliosides have been widely believed to lay essential roles in establishment of the nervous system, especially in neuritogenesis and synaptogenesis. However, this has never(More)
Activity-dependent changes in excitatory synaptic transmission in the CNS have been shown to depend on the regulation of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors (AMPARs). In particular, several lines of evidence suggest that reversible phosphorylation of AMPAR subunit glutamate receptor 1 (GluR1, also referred to as GluA1 or(More)