Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0043167 (pertussis)
19,595 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Glutamate-induced glutamate release may be involved in the delayed neuronal death induced by N-methyl-D-aspartate (NMDA). In order to examine a possible modulatory effect of the presynaptic group III mGluRs on glutamate excitotoxicity, the effect of L-2-amino-4-phosphonobutyrate (L-AP4) was examined on NMDA-induced delayed death of mouse cerebellar granule neurons in culture. We found that L-AP4, at high concentration (in the millimolar range), inhibited in a non-competitive manner the NMDA-induced toxicity. This effect was mimicked by high concentration of L-serine-o-phosphate (L-SOP), and was inhibited by pertussis toxin (PTX) indicating the involvement of a Gi/o protein. This suggests the involvement of mGluR7 in the L-AP4 effect, and this was consistent with the detection of both mGluR7 protein and mRNA in these cultured neurons. To examine the mechanism of the L-AP4-induced protection from excitotoxic damage, the effect of L-AP4 on glutamate release was examined. L-AP4 (> or = 1 mM) noncompetitively inhibited by more than 60% the glutamate release induced by NMDA during the insult. We also observed that the 10-min NMDA receptor stimulation resulted in a dramatic increase in the extracellular glutamate concentration reaching 6000% of the control value 24 h after the insult. This large increase was also inhibited when NMDA was applied in the presence of > or = 1 mM L-AP4. Part of the L-AP4-induced protection from excitotoxic damage of granule neurons may therefore result from the inhibition of the vicious cycle: dying cells release glutamate, glutamate induced cell death. The present results add to the hypothesis that presynaptic mGluRs, probably mGluR7, may be the targets of drugs decreasing glutamate release and then neuronal death observed in some pathological situations.
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PMID:mGluR7-like metabotropic glutamate receptors inhibit NMDA-mediated excitotoxicity in cultured mouse cerebellar granule neurons. 1005 67

Natural polyamines have been proposed to induce histamine release from mast cells through a direct interaction with G proteins. Alternatively, the polyamine binding site of ionotropic N-methyl-D-aspartate (NMDA) receptors has been suggested as a target for spermine on mast cells. We reexamined both hypotheses. Incubation of rat peritoneal mast cells with spermine resulted in a concentration-dependent histamine release (EC50 270 microM). Incubation with NMDA receptor agonists, glutamate or NMDA, associated to the co-agonist glycine, did not induce secretion. Western blot experiments did not reveal NMDA R1, R2a, R2b or R2c subunit expression in rat peritoneal mast cell membranes. The NMDA receptor antagonist at the glycine site, L-689,560, did not modify, at relevant concentrations, the spermine-induced secretion. The NMDA receptor antagonists, ifenprodil and LY 235959, and the NMDA channel blocker, MK801, slightly inhibited, at high concentrations, the secretory effect of spermine. The polyamine arcaine, an antagonist of the NMDA receptor polyamine binding site, induced histamine secretion (EC50 350 microM). Both spermine- and arcaine-induced effects were independent upon extracellular calcium and were largely inhibited by treatment of mast cells with pertussis toxin or benzalkonium chloride. The response to spermine and arcaine was prevented by the hydrolysis of sialic acid residues of the cell surface by neuraminidase, and was restored by permeabilization of the plasma membrane with streptolysine-O, indicating that polyamines act intracellularly. These results confirm the involvement of pertussis toxin-sensitive G proteins in the secretory effect of polyamines and demonstrate the absence of NMDA receptors on rat peritoneal mast cells. Nonselective effects of some NMDA receptor ligands on mast cells cannot be excluded.
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PMID:Effect of NMDA receptor ligands on mast cell histamine release, a reappraisal. 1043 64

Amyloid beta protein (Abeta) alters signal transduction systems, including increases in the cytosolic free calcium ([Ca2+]i) response which have pathophysiological significance in Alzheimer's disease (AD). The purposes of this study were to elucidate the mechanism involved in Abeta's effect on the Ca2+ signal and to evaluate the effect of fullerenol-1, a water-soluble hydroxyl and superoxide radical scavenger, on the Abeta-induced Ca2+ response. Both Abeta and bradykinin (BK) dose-dependently elevated [Ca2+]i in PC12 cells. Fullerenol-1, at a concentration range between 100 nM and 1 microM, dose-dependently reduced the Abeta-induced [Ca2+]i response, but did not alter the subsequent BK-mediated process. Thapsigargin, an inhibitor of Ca2+-ATPase, released Ca2+ from the internal store and diminished the BK-mediated calcium spike but did not affect the Abeta-induced Ca2+ response. In the absence of extracellular calcium, the Abeta-induced, but not BK-induced, calcium spike was completely abolished. The Ca induced by Abeta did not enter through the voltage-dependent calcium channels or ligand gated calcium channels, because the peak of Abeta-evoked Ca2+ was not significantly altered by various Ca2+ channel blockers or a NMDA receptor antagonist MK801. In addition, neither cholera toxin nor pertussis toxin altered the Abeta-induced Ca response. The results demonstrated that Abeta-stimulated [Ca2+]i increase is due to Ca influx from an extracellular source rather than from the intracellular store. Alteration of the membrane lipid structure and permeability by free radicals generated by Abeta may be a major cause of Ca -influx. Furthermore, fullerenol-1, a novel antioxidant, may provide therapeutic benefits in neurodegenerative diseases such as AD.
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PMID:Blockage of amyloid beta peptide-induced cytosolic free calcium by fullerenol-1, carboxylate C60 in PC12 cells. 1079

N-methyl-D-aspartate (NMDA) receptors exist on noradrenergic axon terminals and mediate enhancement of noradrenaline (NA) release. We here investigated modulation by somatostatin (SRIF, somatotropin release inhibiting factor) of the NMDA-induced release of NA using superfused hippocampal synaptosomes. The NMDA response was increased by SRIF-28 and SRIF-14, but not SRIF-28((1 - 14)), whereas the release of [(3)H]-NA elicited by alpha-amino-3-hydroxy-5-methylisoxazide-4-propionic acid (AMPA) was unaffected. SRIF-14 did not mimic glycine at the NMDA receptor but activated SRIF receptors sited on noradrenergic terminals. The SRIF-14 effect was blocked by pertussis toxin but mimicked by mastoparan, a G-protein activator. BIM-23056, but not Cyanamid 154806, antagonized the SRIF-14 effect. This effect was mimicked by L362855, a partial agonist at the sst(5) subtype, but not by the new selective sst(1) - sst(4) receptor agonists L797591, L779976, L796778 and L803087. Protein kinase C (PKC) inhibitors (H7, staurosporine, GF 209103X, cheleritrine and sphingosine) prevented the SRIF-14 effect, while phorbol 12-myristate 13-acetate enhanced the NMDA response. SRIF-14 permitted NMDA receptor activation in the presence of 1.2 mM Mg(2+) ions, both in hippocampal synaptosomes and slices. Blockade of inositol-1,4,5-trisphosphate (InsP(3)) receptors with heparin abolished the effect of SRIF-14. It is concluded that SRIF receptors, possibly of the sst(5) subtype, can exert a permissive role on NMDA receptors colocalized on hippocampal noradrenergic terminals: activation of sst(5) receptors is coupled to pertussis toxin-sensitive G proteins enhancing phosphoinositide metabolism with activation of InsP(3) receptors and PKC; NMDA receptor subunits might be phosphorylated with consequent removal of the Mg(2+) block in absence of depolarization.
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PMID:Somatostatin potentiates NMDA receptor function via activation of InsP(3) receptors and PKC leading to removal of the Mg(2+) block without depolarization. 1082 83

N-Methyl D-aspartate (NMDA) receptor activation of extracellular-signal regulated kinase (ERK) was examined in primary cortical cultures. Tetrodotoxin, NMDA receptor antagonists, or reduced extracellular calcium (0.1 mm) greatly decreased basal levels of phospho-ERK2, indicating that activity-dependent activation of NMDA receptors maintained a high level of basal ERK2 activation. This activity-dependent activation of phospho-ERK2 was blocked by pertussis toxin and inhibition of calcium/calmodulin-dependent kinase II and phosphatidylinositol 3-kinase but not by inhibition of protein kinase C or cAMP-dependent protein kinase. Addition of a calcium ionophore or 100 microm NMDA decreased phospho-ERK2 in the presence of 1 mm extracellular calcium but enhanced phospho-ERK2 in 0.1 mm extracellular calcium. The reduction in basal phospho-ERK2 by 100 microm NMDA was also reflected as a decrease in phospho-cAMP response element-binding protein. Inhibition of tyrosine phosphatases and serine/threonine phosphatases protein phosphatase 1 (PP1), PP2A, and PP2B did not prevent the inhibitory effect of NMDA. In the presence of tetrodotoxin, NMDA produced a bell-shaped dose-response curve with stimulation of phospho-ERK2 at 10, 25, and 50 microm NMDA and reduced stimulation at 100 microm NMDA. NMDA (50 microm) stimulation of phospho-ERK2 was completely blocked by pertussis toxin and inhibitors of phosphatidylinositol 3-kinase and was partially blocked by a calcium/calmodulin-dependent kinase II inhibitor. These results suggests that NMDA receptors can bidirectionally control ERK signaling.
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PMID:N-methyl D-aspartate receptor-mediated bidirectional control of extracellular signal-regulated kinase activity in cortical neuronal cultures. 1106 37

Using mouse hippocampal slices, we studied the induction of depotentiation of long-term potentiation (LTP) at the mossy fiber synapses onto CA3 pyramidal neurons. A long train of low-frequency (1 Hz/900 pulses) stimulation (LFS) induced a long-term depression of baseline synaptic transmission or depotentiation of previously established LTP, which was reversible and was independent of NMDA receptor activation. This LFS-induced depotentiation was observed when the stimulus was delivered 1 or 10 min after LTP induction. However, when LFS was applied at 30 min after induction, significantly less depotentiation was found. The induction of depotentiation on one input was associated with a heterosynaptic reverse of the LTP induced previously on a separate pathway. In addition, this LFS-induced depotentiation appeared to be mediated by the activation of group 2 metabotropic glutamate receptors (mGluRs), because it was mimicked by the bath-applied group 2 agonist (2S,2'R,3'R)-2-(2', 3'-dicarboxycyclopropyl) glycine and was specifically inhibited by the group 2 antagonists (S)-alpha-methyl-4-carboxyphenylglycine and (alphaS)-alpha-amino-alpha-(1S,2S)-2-carboxycyclopropyl-9H-xanthine-9-propanic acid. Moreover, the induction of depotentiation was entirely normal when synaptic transmission is blocked by glutamate receptor antagonist kynurenic acid and was associated with a reversal of paired-pulse facilitation attenuation during LTP expression. Pretreatment of the hippocampal slices with G(i/o)-protein inhibitor pertussis toxin (PTX) prevented the LFS-induced depotentiation. These results suggest that the activation of presynaptic group 2 mGluRs and in turn triggering a PTX-sensitive G(i/o)-protein-coupled signaling cascade may contribute to the LFS-induced depotentiation at the mossy fiber-CA3 synapses.
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PMID:Time-dependent reversal of long-term potentiation by low-frequency stimulation at the hippocampal mossy fiber-CA3 synapses. 1135 57

Toxic effects of HIV-1 proteins contribute to altered function and decreased survival of select populations of neurons in HIV-1-infected brain. One such HIV-1 protein, Tat, can activate calcium release from IP3-sensitive intracellular pools, induce calcium influx in neural cells, and, as a result, can increase neuronal cell death. Here, we provide evidence that Tat potentiates excitatory amino acid (glutamate and NMDA) triggered calcium flux, as well as glutamate- and staurosporine-mediated neurotoxicity. Calcium flux in cultured rat hippocampal neurons triggered by the transient application of glutamate or NMDA was facilitated by pre-exposure to Tat. Facilitation of glutamate-triggered calcium flux by Tat was prevented by inhibitors of ADP-ribosylation of G(i)/G(o) proteins (pertussis toxin), protein kinase C (H7 and bisindolymide), and IP3-mediated calcium release (xestospongin C), but was not prevented by an activator of G(s) (cholera toxin) or an inhibitor of protein kinase A (H89). Facilitation of NMDA-triggered calcium flux by Tat was reversed by inhibitors of tyrosine kinase (genestein and herbimycin A) and by an inhibitor of NMDA receptor function (zinc). Tat increased 32P incorporation into NMDA receptor subunits NR2A and NR2B and this effect was blocked by genestein. Subtoxic concentrations of Tat combined with subtoxic concentrations of glutamate or staurosporine increased neuronal cell death significantly. Together, these findings suggest that NMDA receptors play an important role in Tat neurotoxicity and the mechanisms identified may provide additional therapeutic targets for the treatment of HIV-1 associated dementia.
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PMID:HIV-1 Tat through phosphorylation of NMDA receptors potentiates glutamate excitotoxicity. 1148 48

Ca2+ influx through NMDA receptors can initiate molecular changes in neurones which may underlie synaptic plasticity, neuronal development, survival and excitotoxicity. Signalling through the MAP kinase (Erk1/2) cascade may be central to these processes. We previously demonstrated that Ca2+-permeable AMPA receptors activate Erkl/2 through a phosphatidylinositol 3-kinase (PI 3-kinase)-dependent mechanism. We now report that NMDA receptor activation of Erk1/2 was also blocked by inhibitors of PI 3-kinase (LY 294002, wortmannin). In addition, pre-treatment of neurones with pertussis toxin inhibited NMDA-induced Erk1/2 activation, indicating a role for heterotrimeric Gi/o proteins. PI 3-kinase directs activation of the serine-threonine kinase Akt (PKB). Treatment of striatal neurones with glutamate induced a rapid Ca2+-dependent and PI 3-kinase-dependent phosphorylation of Akt (Ser473), which was not blocked by the Mek inhibitors PD98059 or U0126. Targets for Erk1/2 and Akt pathways include transcription factors. Glutamate-induced phosphorylation of cAMP response element binding protein (CREB; Ser133) was partially blocked with either PD98059, U0126, LY294002 or wortmannin but was very strongly inhibited on co-application of LY294002 and PD98059. We propose that NMDA receptor stimulation can activate Erk1/2 and Akt signalling pathways in a PI 3-kinase dependent manner which may target CREB in the nucleus.
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PMID:Phosphatidylinositol 3-kinase is a central mediator of NMDA receptor signalling to MAP kinase (Erk1/2), Akt/PKB and CREB in striatal neurones. 1190 14

The aim of the present study was to examine the effect of intrathecal (i.t.) injection of pertussis toxin (PTX) on the nociceptive threshold and protein kinase C (PKC) expression in the rat spinal cord. The role of N-methyl-D-aspartic acid (NMDA) receptors in these changes was also examined. Male Wistar rats were implanted with two i.t. catheters, one of which was connected to a mini-osmotic pump and used to infuse saline or D-2-amino-5-phosphonopentanoic acid (D-AP5) (2 microg/h) starting on day 3 after i.t. catheter insertion. Two days later, a single injection of saline or PTX (2 microg) was given via the other catheter, followed by a flush with 10 microl of saline. On day 4 after PTX or saline injection, the thermal paw withdrawal latency was measured, then the rats were sacrificed by decapitation, and the dorsal part of the lumbosacral spinal segments was removed for PKC Western blotting assays. In PTX-treated rats, thermal hyperalgesia was observed, and the PKCgamma content of both the synaptosomal membrane and cytosolic fractions was significantly increased. The levels of alpha-, betaI-, or betaII-PKC isozymes in these fractions were unaffected by PTX treatment. Infusion of the NMDA antagonist, D-AP5, prevented both the thermal hyperalgesia and the increase in PKCgamma isoform expression in PTX-treated rats, and had no effect on these values in nai;ve rats. Intrathecal injection of the PKC inhibitor, chelerythrine (10 microg), significantly inhibited the thermal hyperalgesia observed in PTX-treated rats. These results show that i.t. injection of PTX induced thermal hyperalgesia accompanied by a selective increase in PKCgamma expression in both the synaptosomal membrane and cytosolic fractions of the dorsal horn of the rat lumbar spinal cord, and both effects were inhibited by the NMDA receptor antagonist, D-AP5.
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PMID:D-2-amino-5-phosphonopentanoic acid inhibits intrathecal pertussis toxin-induced thermal hyperalgesia and protein kinase Cgamma up-regulation. 1256 Jan 6

Nociceptin (also called orphanin FQ) is an endogenous heptadecapeptide that activates the opioid receptor-like 1 (ORL1) receptor. Nociceptin system not only affects the nociception and locomotor activity, but also regulates learning and memory in rodents. We have previously reported that long-term potentiation and memory of ORL1 receptor knockout mice are enhanced compared with those in wild-type mice. Here, we show the neuronal mechanism of nociceptin-induced modulation of learning and memory. Retention of fear-conditioned contextual memory was significantly enhanced in the ORL1 receptor knockout mice without any changes in cued conditioned freezing. Inversely, in the wild-type mice retention of contextual, but not cued, conditioning freezing behavior was suppressed by exogenous nociceptin when it was administered into the cerebroventricle immediately after the training. ORL1 receptor knockout mice exhibited a hyperfunction of N-methyl-D-aspartate (NMDA) receptor, as evidenced by an increase in [3H]MK-801 binding, NMDA-evoked 45Ca2+ uptake and activation of Ca2+/calmodulin-dependent protein kinase II (CaMKII) activity and its phosphorylation as compared with those in wild-type mice. The NMDA-induced CaMKII activation in the hippocampal slices of wild-type mice was significantly inhibited by exogenous nociceptin via a pertussis toxin-sensitive pathway. However, the alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor GluR1 subunit at Ser831 and Ser845, and NMDA receptor subunit NR2B at Thr286 were phosphorylated similarly after NMDA receptor stimulation in both type of mice. The expressions of GluR1 and GluR2 also did not change, but the levels of polysialylated form of neuronal cell adhesion molecule (N-CAM) were reduced in the ORL1 receptor knockout as compared with wild-type mice. These results suggest that nociceptin system negatively modulates learning and memory through the regulation of NMDA receptor function and the expression of N-CAM.
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PMID:Neuronal mechanism of nociceptin-induced modulation of learning and memory: involvement of N-methyl-D-aspartate receptors. 1288 4


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