Modulation of DL-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid/quisqualate receptors by phospholipase A2: a necessary step in long-term potentiation?

Massicotte, Guy; Vanderklish, Pete; Lynch, Gary; Baudry, Michel

doi:10.1073/pnas.88.5.1893

Cited by 62 publications

(38 citation statements)

References 25 publications

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“…Added to this is the demonstration that AMPA receptors are sensitive to changes in the membrane/cytoskeletal environment in which they are embedded (Terramani et al 1988;Massicotte et al 1991;Hall et al 1992). In this context, the present observations are consistent with a view of LTP that regards ( 1 ) expres-…”

Section: Discussionsupporting

confidence: 81%

Translational suppression of calpain blocks long-term potentiation.

Vanderklish

Bednarski²,

Lynch³

1996

Learning & Memory

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Transfection with antisense oligonucleotides was used to reduce calpain 1 activity to -50% of normal values in cultured hippocampal slices. This had no detectable effects on baseline synaptic responses but greatly reduced the incidence and magnitude of long-term potentiation induced with a 0-burst stimulation paradigm. These results suggest that activation of calpain by repetitive bursts of afferent activity, as shown to occur in prior studies, is an essential step in the production of stable increases in synaptic strength.

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Section: Discussionsupporting

confidence: 81%

Translational suppression of calpain blocks long-term potentiation.

Vanderklish

Bednarski²,

Lynch³

1996

Learning & Memory

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“…Inhibition of the PLA 2 -induced Modulation of AMPA Binding by the CSD Peptide-Because several studies indicate that calcium-dependent PLA 2 participates in selective changes in AMPA receptor properties (33,35), the previous results prompted us to examine the possibility that the inhibition of cPLA 2 activity could interfere with AMPA receptor binding. Double immunofluorescence was first used to examine whether caveolin-1 and AMPA receptors are co-localized at the cellular level.…”

Section: Cpla 2 Localization In Caveolin-rich Microdomains Andmentioning

confidence: 99%

The Caveolin Scaffolding Domain Modifies 2-Amino-3-hydroxy-5-methyl-4-isoxazole Propionate Receptor Binding Properties by Inhibiting Phospholipase A2 Activity

Gaudreault

Chabot

Gratton

et al. 2004

Journal of Biological Chemistry

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Activation of the enzyme phospholipase (PLA 2 ) has been proposed to be part of the molecular mechanism involved in the alteration of 2-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) glutamate receptor responsiveness during long term changes in synaptic plasticity (long term potentiation). This study assesses the effect of the caveolin-1 scaffolding domain (CSD) on the activity of the regulatory enzyme PLA 2 . Caveolin-1 is a 22-kDa cholesterol-binding membrane protein known to inhibit the activity of most of its interacting partners. Our results show that the calcium-dependent cytosolic form of PLA 2 (cPLA 2 ) and caveolin-1 co-localized in mouse primary hippocampal neuron cultures and that they were co-immunoprecipitated from mouse hippocampal homogenates. A peptide corresponding to the scaffolding domain of caveolin-1 (Cav-(82-101)) dramatically inhibited cPLA 2 activity in purified hippocampal synaptoneurosomes. Activation of endogenous PLA 2 activity with KCl or melittin increased the binding of [ 3 H]AMPA to its receptor. This effect was almost completely abolished by the addition of the CSD peptide to these preparations. Moreover, we demonstrated that the inhibitory action of the CSD peptide on AMPA receptor binding properties is specific (because a scrambled version of this peptide failed to have any effect) and that it is mediated by an inhibition of PLA 2 enzymatic activity (because the CSD peptide failed to have an effect in membrane preparations lacking endogenous PLA 2 activity). These results raised the possibility that caveolin-1, via the inhibition of cPLA 2 enzymatic activity, may interfere with synaptic facilitation and long term potentiation formation in the hippocampus.Phospholipase (PLA 2 ) 1 belongs to a superfamily of enzymes that play a central role in the regulation of arachidonic acid (AA) release from membrane phospholipids and catalyze the production of various metabolites. PLA 2 activity has been postulated to play an important role in key metabolic pathways. In addition to its involvement in signal transduction, membrane repair, neurodegeneration, and apoptosis (1), there is a growing body of evidence suggesting a role in the modulation of neurotransmitter release and long term potentiation (LTP) (2-4). Changes in synaptic function observed with LTP are thought to be the result of modifications of postsynaptic currents mediated by the 2-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) subtype of glutamate receptors (5, 6). PLA 2 activity was shown to be part of the molecular mechanisms regulating AMPA receptor function during long term changes in synaptic operation (7-9). It has been proposed that during high frequency stimulation a large entry of calcium mediated by N-methyl-D-aspartate (NMDA) glutamate receptor activation might cause an increase in PLA 2 activity. The enzyme would augment AMPA receptor affinity by changing the lipid environment of AMPA receptors, thereby producing LTP (10). Recently, it has been reported that detergent-insoluble caveolin-rich membran...

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“…Nevertheless, it is noteworthy that activation of the calcium-dependent enzyme phospholipase A 2 (PLA 2 ) could be part of the molecular mechanisms underlying changes in AMPA receptor conformation. In particular, it was reported previously that treatment of telencephalic membranes or tissue sections with exogenous PLA 2 or phospholipase C (PLC) heightened AMPA receptor affinity [39,40,41,42]. Various studies have suggested that the effect of phospholipases could be due to modifications of the lipid environment of the receptors, as incorporation of phosphatidylserine (PS) into rat brain membranes reproduced the increased affinity of AMPA receptors elicited by calcium-dependent phospholipases [43].…”

Section: Discussionmentioning

confidence: 99%

Up-regulation of glutamate receptors is associated with LTP defects in the early stages of diabetes mellitus

et al. 2002

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Aims/hypothesis. Recent studies involving electrophysiology and immunolabelling indicate that shortterm insulin treatment of hippocampal neurons in culture induces changes in glutamate receptor function, suggesting that this receptor system can be altered on a relatively rapid time scale during diabetic conditions. To investigate this hypothesis, we examined whether brain glutamate receptors and long-term potentiation are altered in the early stages of diabetes mellitus in non-obese diabetic mice, a genetic model of Type I (insulin-dependent) diabetes mellitus. Methods. In vitro receptor autoradiography and immunoblotting were used to study the impact of diabetes on brain glutamate receptors. From an electrophysiological point of view, field potential recordings were also examined in area CA1 of hippocampal slices to determine the influence of diabetes on long-term potentiation.Results. Quantitative autoradiographic analysis revealed enhanced 3 H-glutamate binding to several brain regions of diabetes mice, with maximal increases in the cerebral cortex and hippocampus. Saturation kinetics within the cerebral cortex disclosed that this change of 3 H-glutamate was possibly due to an increase in the maximal number of N-methyl-D-aspartate binding sites, an interpretation that was corroborated by Western blot analysis of N-methyl-D-aspartate 2A subunits. Impairment in the expression of hippocampal long-term potentiation was also observed in diabetic mice, while the failure to elicit synaptic potentiation was prevented by insulin treatment. Conclusion/interpretation. Because glutamate receptors are thought to be involved in several degenerative processes, our results suggest that up-regulation of these receptors in the early stages of diabetes could represent an important mechanism underlying neurological complications within the brain of diabetic patients. [Diabetologia (2002) 45:642-650] Keywords NMDA receptor, AMPA receptor, hippocampus, NOD mice. According to recent projections, over 200 million people worldwide will be diagnosed with diabetes by the year 2010 [1]. Diabetes mellitus is an endocrine disorder of carbohydrate metabolism resulting primarily from inadequate insulin release (Type I insulin-dependent diabetes mellitus) or insulin insensitivity coupled with inadequate compensatory insulin release (Type II non-insulin-dependent diabetes mellitus). Forms of diabetes are associated with the development of complications in the peripheral as well as the central nervous system (CNS). For instance, learning and memory deficits are linked with Type I and Type II diabetes mellitus [2, 3, 4, 5, 6], and brain morphological abnor-

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Modulation of DL-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid/quisqualate receptors by phospholipase A2: a necessary step in long-term potentiation?

Cited by 62 publications

References 25 publications

Translational suppression of calpain blocks long-term potentiation.

Translational suppression of calpain blocks long-term potentiation.

The Caveolin Scaffolding Domain Modifies 2-Amino-3-hydroxy-5-methyl-4-isoxazole Propionate Receptor Binding Properties by Inhibiting Phospholipase A2 Activity

Up-regulation of glutamate receptors is associated with LTP defects in the early stages of diabetes mellitus

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