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Calpains have been previously shown to regulate AMPA receptor properties by producing partial truncation of the C-terminal domains of several receptor subunits. We now report that NMDA receptor subunits, in particular NR2 subunits, are also subjected to calpain-mediated truncation. Treatment of synaptic membranes with calpain I resulted in truncation of(More)
The AMPA receptors are glutamate-gated ion channels mediating synaptic transmission at the majority of excitatory synapses in the mammalian CNS. They are composed of four subunits (GluR1-4) which exist in two alternatively spliced variants (flip and flop) and are generally considered to form pentameric receptors. The transmembrane structure of the receptors(More)
Global long-term potentiation (LTP) was induced in organotypic hippocampal slice cultures by a brief application of 10 mM glycine. Glycine-induced LTP was occluded by previous theta burst stimulation-induced potentiation, indicating that both phenomena share similar cellular processes. Glycine-induced LTP was associated with increased(More)
Pre-incubation of synaptic membranes with phosphatase inhibitors significantly reduces the extent of calpain-mediated truncation of both GluR1 and NR2 subunits of AMPA and NMDA receptors, respectively. The same treatment did not modify calpain-mediated truncation of spectrin. These results might have important implications for mechanisms of synaptic(More)
The present study examined changes in GluR1 subunits after kainic acid (KA) treatment of organotypic hippocampal cultures. Immunoblots labeled with antibodies directed at the C-terminal domain of GluR1 revealed a large decrease in GluR1 immunoreactivity at 6 h and 24 h, while immunoblots labeled with antibodies directed at the N-terminal domain indicated(More)
Activation of the calcium-dependent protease calpain has been proposed to be a necessary step in the formation of long-term potentiation (LTP) in the hippocampus, and stimulation of N-methyl-D-aspartate (NMDA) receptors leads to an increase in intracellular calcium concentration, calpain activation, proteolysis of cytoskeletal elements, and modification of(More)
Systemic injection of kainic acid (KA) in adult rat elicits a pattern of neuronal pathology which exhibits several features of human temporal lobe epilepsy. KA-induced seizure activity is accompanied by the activation of the calcium-dependent protease calpain in limbic structures. In the present study, we evaluated the spatio-temporal activation of calpain(More)
Previous results have indicated that GluR1 subunits of alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) receptors are targets of calpain. In the present study, we determined the effects of calpain treatment of synaptic membranes on GluR1 subunits using western blots with antibodies directed against the C-terminal (C-Ab) and the N-terminal (N-Ab)(More)
The synaptotagmins together with other vesicle proteins are thought to be essential for the docking and/or fusion of synaptic vesicles with the plasma membrane that occurs following depolarization and calcium influx in presynatic terminals. Syt4, the fourth identified member of the synaptotagmin family, is inducible in PC12 cells by depolarization and(More)
The cellular distribution of calpain activation and glutamate receptor 1 (GluR1) subunits of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors and their alterations following kainic acid-induced seizure were evaluated during postnatal development using antibodies specific for spectrin breakdown product and the C-terminus of GluR1 subunits.(More)