Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0040822 (tremor)
 18,428 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The muscarinic agonist arecoline (6 mg/kg, subcutaneously in mice) induced a long-lasting tremor. The inhibitory potency of non-competitive antagonists of ionotropic glutamate receptors has been studied. These antagonists are the derivatives of adamantane and phenylcyclohexyl. A part of them: monocationic compounds, selectively block the NMDA-receptor channels, their dicationic analogues affecting both channels of the NMDA- and the AMPA-glutamate receptors. Monocationic blockers effectively reduced the arecoline-evoked tremor and their potency correlated with ability to block the NMDA-receptor channels. Dicationic blockers revealed protective effect only in low range doses (0.0001-0.01 microM/kg). Further increase of the dose reduced or completely abolished this effect. This suggests that the NMDA-receptors are involved in the genesis of arecoline-evoked tremor. The only moderate blockade of the AMPA-receptors potentiates the drug blocking action but the prevalent blockade of these receptors impedes the effect on arecoline-evoked tremor.
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PMID:[Involvement of ionotropic glutamate receptors in the genesis of arecoline-induced tremor]. 1759 70

Future therapies in Parkinson's disease may substantially build on the existence of intra-membrane receptor-receptor interactions in DA receptor containing heteromeric receptor complexes. The A(2A)/D(2) heteromer is of substantial interest in view of its specific location in cortico-striatal glutamate terminals and in striato-pallidal GABA neurons. Antagonistic A(2A)/D(2) receptor interactions in this heteromer demonstrated at the cellular level, and at the level of the striato-pallidal GABA neuron and at the network level made it possible to suggest A(2A) antagonists as anti-parkinsonian drugs. The major mechanism is an enhancement of D(2) signaling leading to attenuation of hypokinesia, tremor, and rigidity in models of Parkinson's disease with inspiring results in two clinical trials. Other interactions are antagonism at the level of the adenylyl cyclase; heterologous sensitization at the A(2A) activated adenylyl cyclase by persistent D(2) activation and a compensatory up-regulation of A(2A) receptors in response to intermittent Levodopa treatment. An increased dominance of A(2A) homomers over D(2) homomers and A(2A)/D(2) heteromers after intermittent Levodopa treatment may therefore contribute to development of Levodopa induced dyskinesias and to the wearing off of the therapeutic actions of Levodopa giving additional therapeutic roles of A(2A) antagonists. Their neuroprotective actions may involve an increase in the retrograde trophic signaling in the nigro-striatal DA system.
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PMID:Adenosine A(2A) receptors, dopamine D(2) receptors and their interactions in Parkinson's disease. 1761 24

High N-acetyl-L-aspartate (NAA) levels prevail as a free amino acid in vertebrate brains. NAA is synthesized from aspartate and acetyl Co-A, or is liberated by the hydrolyzation of N-acetyl-L-aspartyl-glutamate in mitochondria before being metabolized by aspartoacylase to aspartate and acetate in the cytosol of glial cells. The tremor rat (tm/tm), derived from a Kyoto-Wistar colony, shows absence-like seizures with 5- to 7-Hz spike-wave-like complexes in cortical and hippocampal electroencephalograms (EEG). Genomic microdeletion was found within the aspartoacylase-encoding tm critical region, where an increase in the NAA level was noted. Intracerebroventricular NAA induced absence-like seizures, convulsive seizures or both in epileptic EEG of Wistar rats. NAA activated the hippocampal CA3 neurons of Wistar rats via the metabotropic glutamate receptor (mGluR) in acutely dissociated hippocampal CA3 neurons. The mechanism of NAA action on CA3 neurons was examined with intracellular recording of Wistar and tremor rat hippocampal slices to evaluate the role of NAA in neuronal networks. Bath application of NAA (10 microM-1mM) dose-dependently induced depolarization in CA3 neurons of Wistar and tremor rats. Cadmium (a Ca(2+) channel antagonist) and GDEE (an ionotropic glutamate receptor antagonist) did not affect NAA-induced depolarization. Although ACPD (a nonspecific mGluR agonist) induced similar depolarizations in CA3 neurons, MCPG (a mGluR antagonist) inhibited NAA-induced depolarization. These results suggest that NAA probably activates hippocampal CA3 neurons via the mGluR in a neuronal network.
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PMID:N-acetyl-L-aspartate activates hippocampal CA3 neurons in rodent slice preparations. 1835 43

The present study investigated the role of peripheral group I metabotropic glutamate receptors (mGluRs) in MO-induced nociceptive behaviour and inflammation in the masseter muscles of lightly anesthetized rats. Experiments were carried out on male Sprague-Dawley rats weighing 300-400 g. After initial anesthesia with sodium pentobarbital (40 mg/kg, i.p.), one femoral vein was cannulated and connected to an infusion pump for intravenous infusion of sodium pentobarbital. The rate of infusion was adjusted to provide a constant level of anesthesia. Mustard oil (MO, 30 microl) was injected into the mid-region of the left masseter muscle via a 30-gauge needle over 10s. After 30 microl injection of 5, 10, 15, or 20% MO into the masseter muscle, the total number of hindpaw shaking behaviour and extravasated Evans' blue dye concentration in the masseter muscle were significantly higher in the MO-treated group in a dose-dependent manner compared with the vehicle (mineral oil)-treated group. Intramuscular pretreatment with 3 or 5% lidocaine reduced MO-induced hindpaw shaking behaviour and increases in extravasated Evans' blue dye concentration. Intramuscular pretreatment with 5mM MCPG, non-selective group I/II mGluR antagonist, or MPEP, a selective group I mGluR5 antagonist, produced a significant attenuation of MO-induced hindpaw shaking behaviour and increases in extravasated Evans' blue dye concentration in the masseter muscle while LY367385, a selective group I mGluR1 antagonist, did not affect MO-induced nociceptive behaviour and inflammation in the masseter muscle. These results indicate that peripheral mGluR5 plays important role in mediating MO-induced nociceptive behaviour and inflammation in the craniofacial muscle.
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PMID:WITHDRAWN: Peripheral mGluR5 antagonist attenuated craniofacial muscle pain and inflammation but not mGluR1 antagonist in lightly anesthetized rats. 1839 5

Administration of the muscarinic cholinoreceptor agonist arecoline (6 mg/kg, s.c.) to mice induced long-lasting tremor. The ability of non-competitive antagonists of ionotropic glutamate receptors to suppress the onset of tremor was studied. These antagonists, i.e., adamantane and phenylcyclohexyl derivatives, selectively blocked NMDA-type receptor channels (monocations) or both NMDA-and AMPA-type channels (dications). Both types of blocker weakened arecoline tremor, though the dose-response relationships were different for mono-and dications. The effects of dications appeared only at low blocker doses (0.0001-0.01 micromol/kg) but gradually disappeared on dose elevation. These data lead to the conclusion that the mechanism of pathogenesis of arecoline tremor predominantly involves NMDA-type receptors. Moderate blockade of AMPA-type receptors could potentiate the preventive effect of mixed-action antagonists (anti-NMDA+anti-AMPA), though predominance of blocking action against AMPA-type receptors prevented this effect.
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PMID:Involvement of ionotropic glutamate receptors in the appearance of arecoline tremor in mice. 1840 36

Adenosine A(2A) receptors present in the central nervous system have been implicated in the modulation of motor functions. Accordingly, adenosine A(2A) receptor antagonists currently constitute an attractive non-dopaminergic option for use in the treatment of Parkinson's disease (PD). The highly enriched distributions of adenosine A(2A) receptors in striatopallidal neurons, and their ability to form functional heteromeric complexes with dopamine D(2) and metabotropic glutamate mGlu5 receptors, render A(2A) receptor antagonists of particular interest in the modulation of motor behavior, whilst at the same time displaying a low predisposition to inducing non-motor side effects. Furthermore, adenosine A(2A) receptor antagonists appear to exert a marked efficacy on PD tremor and in reducing the progress of underlying neurodegeneration and maladaptive neuroplasticity that complicates standard dopamine replacement treatments in PD. Finally, recent evidence has illustrated an improvement of cognitive function as well as enhancement of attention in rodents following administration of A(2A) receptor antagonists. This article is aimed at examining preclinical studies describing these findings as well as reports from clinical trials, in order to provide a comprehensive review of the evidence suggesting that this class of drugs may represent an advance in the treatment of PD.
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PMID:Adenosine A2A receptor antagonists and Parkinson's disease: state of the art and future directions. 1853 71

Parkinson's disease (PD) is caused by the death of dopamine neurons in the basal ganglia and results in motor symptoms such as tremor and bradykinesia. Activation of metabotropic glutamate receptor 4 (mGluR4) has been shown to modulate neurotransmission in the basal ganglia and results in antiparkinsonian effects in rodent PD models. N-Phenyl-7-(hydroxyimino)cyclopropa[b]chromen-1a-carboxamide (PHCCC) is a positive allosteric modulator (PAM) of mGluR4 that has been used to further validate the role of mGluR4 in PD, but the compound suffers from a lack of selectivity, relatively low potency, and poor solubility. Via high-throughput screening, we discovered more than 400 novel PAMs of mGluR4. Compounds derived from a novel chemical scaffold were characterized in vitro at both rat and human mGluR4 using two distinct assays of mGluR4 function. The lead compound was approximately 8-fold more potent than PHCCC, enhanced the potency of glutamate at mGluR4 by 8-fold, and did not show any significant potentiator or antagonist activity at other mGluR subtypes. Resolution of the regioisomers of the lead revealed that the cis regioisomer, (+/-)-cis-2-(3,5-dichlorphenylcarbamoyl)cyclohexanecarboxylic acid (VU0155041), contained the majority of the mGluR4 PAM activity and also exhibited partial agonist activity at mGluR4 at a site that was distinct from the glutamate binding site, suggesting that this compound is a mixed allosteric agonist/PAM of mGluR4. VU0155041 was soluble in an aqueous vehicle, and intracerebroventricular administration of 31 to 316 nmol of VU0155041 dose-dependently decreased haloperidol-induced catalepsy and reserpine-induced akinesia in rats. These exciting results provide continued support for mGluR4 as a therapeutic target in PD.
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PMID:Discovery, characterization, and antiparkinsonian effect of novel positive allosteric modulators of metabotropic glutamate receptor 4. 1866 3

We have reported increased glutamate production by a mutant of Corynebacterium glutamicum ATCC14067 (strain F172-8) with reduced H(+)-ATPase activity under biotin-limiting culture conditions (Aoki et al. Biosci. Biotechnol. Biochem., 69, 1466-1472 (2005)). In the present study, we examined valine production by an H(+)-ATPase-defective mutant of C. glutamicum. Using the double-crossover chromosome replacement technique, we constructed a newly defined H(+)-ATPase-defective mutant from ATCC13032. After transforming the new strain (A-1) with a C-terminal truncation of acetohydroxyacid synthase gene (ilvBN), valine production increased from 21.7 mM for the wild-type strain to 46.7 mM for the A-1 in shaking flask cultures with 555 mM glucose. Increased production of the valine intermediate acetoin was also observed in A-1, and was reduced by inserting acetohydroxyacid isomeroreductase gene (ilvC) into the ilvBN plasmid. After transformation with this new construct, valine production increased from 38.3 mM for the wild-type strain to 95.7 mM for A-1 strain. To the best of our knowledge, this is the first report indicating that an H(+)-ATPase-defective mutant of C. glutamicum is capable of valine production. Our combined results with glutamate and valine suggest that the H(+)-ATPase defect is also effective in the fermentative production of other practical compounds.
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PMID:Enhanced valine production in Corynebacterium glutamicum with defective H+-ATPase and C-terminal truncated acetohydroxyacid synthase. 1899 2

Metabotropic glutamate receptors (mGluRs) represent a potential therapeutic target. Possible anticonvulsant action of AMN 082, an agonist of mGluR7 subtype, was studied in immature rats using pentylenetetrazol (PTZ)-induced seizures as a model. Five age groups of rats (7-, 12-, 18-, 25-day-old and adult animals) were pretreated with AMN 082 in doses of 0.5, 1, 2, and 5 mg/kg i.p. and 30 min later PTZ was administered (100 mg/kg s.c.). Controls received saline instead of the agonist. AMN 082 did not exhibit clear anticonvulsant action with the exception of suppression of the tonic phase of generalized tonic-clonic seizures (GTCS) in 12-day-old rats. Shorter latencies of GTCS after AMN 082 pretreatment indicate a proconvulsant action. Involuntary movements (mostly tremor) appeared after AMN 082 before PTZ administration, therefore we performed another experimental series with AMN 082 only (1, 2, 5, and 10 mg/kg i.p.). During 60-min observation period tremor appeared in all age groups; sensitivity to this action decreased with age from the 2 mg/kg dose in 7- and 12-day-old rats to the 10 mg/kg dose in adult rats. Mixed anti- and proconvulsant actions of AMN 082 together with unwanted motor effects makes clinical use of this drug highly improbable.
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PMID:AMN 082, an agonist of mGluR7, exhibits mixed anti- and proconvulsant effects in developing rats. 1915 87

The experiments on mice C57B1/6 with MPTP-induced Parkinsonian syndrome have shown that preliminary and simultaneous intranasal injection of glutamate antibodies inhibit development of the syndrome. Administration of glutamate antibodies decreased tremor, rigidity and increased horizontal locomotion, movement velocity in the open field.
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PMID:[Glutamate antibodies in the development of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinsonian syndrome in C57B1/6 mice]. 1920 15


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