51
|
Rationale and design of a multicenter randomized clinical trial with memantine and dextromethorphan in ketamine-responder patients. Contemp Clin Trials 2014; 38:314-20. [PMID: 24948402 DOI: 10.1016/j.cct.2014.06.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Revised: 06/03/2014] [Accepted: 06/05/2014] [Indexed: 01/29/2023]
Abstract
The N-methyl-D-aspartate receptor plays an important role in central sensitization of neuropathic pain and N-methyl-D-aspartate receptor antagonists, such as ketamine, memantine and dextromethorphan may be used for persistent pain. However, ketamine cannot be repeated too often because of its adverse events. A drug relay would be helpful in the outpatient to postpone or even cancel the next ketamine infusion. This clinical trial evaluates if memantine and/or dextromethorphan given as a relay to ketamine responders may maintain or induce a decrease of pain intensity and have a beneficial impact on cognition and quality of life. This trial is a multi-center, randomized, controlled and single-blind clinical study (NCT01602185). It includes 60 ketamine responder patients suffering from neuropathic pain. They are randomly allocated to memantine, dextromethorphan or placebo. After ketamine infusion, 60 patients received either memantine (maximal dose 20 mg/day), or dextromethorphan (maximal dose 90 mg/day), or placebo for 12 weeks. The primary endpoint is pain measured on a (0-10) Numeric Rating Scale 1 month after inclusion. Secondary outcomes include assessment of neuropathic pain, sleep, quality of life, anxiety/depression and cognitive function at 2 and 3 months. Data analysis is performed using mixed models and the tests are two-sided, with a type I error set at α=0.05. This study will explore if oral memantine and/or dextromethorphan may be a beneficial relay in ketamine responders and may diminish ketamine infusion frequency. Preservation of cognitive function and quality of life is also a central issue that will be analyzed in these vulnerable patients.
Collapse
|
52
|
Palazzo E, de Novellis V, Rossi F, Maione S. Supraspinal metabotropic glutamate receptor subtype 8: a switch to turn off pain. Amino Acids 2014; 46:1441-8. [PMID: 24623118 DOI: 10.1007/s00726-014-1703-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 02/18/2014] [Indexed: 12/28/2022]
Abstract
Glutamate is the main excitatory neurotransmitter in the central nervous system and as such controls the majority of synapses. Glutamatergic neurotransmission is mediated via ionotropic and metabotropic glutamate receptors (iGluRs and mGluRs). Signaling via mGluRs permits to finely tune, rather than turning on/off, the excitatory neurotransmission as the iGluRs do. Eight mGluRs (mGluR1-8) have been cloned so far, which have been divided into three groups based on sequence homology, pharmacological properties and second messenger signaling. mGluRs are widely expressed both on glia and neurons. On neurons they are located both at postsynaptic (group I) and presynaptic sites (group II and III). Group II and III mGluR stimulation reduces glutamate release, which can prove useful in pathological conditions characterized by elevated glutamatergic neurotransmission which include chronic pain. Indeed, mGluRs are widely distributed on pain neuraxis. The recent development of selective mGluR ligands has permitted investigating the individual role of each mGluR on pain control. The development of (S)-3,4-dicarboxyphenylglycine, a selective mGluR8 agonist, has revealed the mGluR8 role in inhibiting pain and its related affective consequences in chronic pain conditions. mGluR8 proved also to be overexpressed in pain controlling areas during pathological pain guaranteeing the availability of a switch for turning off abnormal pain. Thus, mGluR8 corresponds to an ideal target in designing novel analgesics. This review will focus on the novel insights into the mGluR8 role on pain control, with particular emphasis on the supraspinal descending pathway, an antinociceptive endogenous source, whose activation or disinhibition (via mGluR8) induces analgesia.
Collapse
Affiliation(s)
- Enza Palazzo
- Department of Anaesthesiology, Surgery and Emergency, The Second University of Naples, Piazza Luigi Miraglia 2, 80138, Naples, Italy,
| | | | | | | |
Collapse
|
53
|
Sivarao DV, Chen P, Yang Y, Li YW, Pieschl R, Ahlijanian MK. NR2B Antagonist CP-101,606 Abolishes Pitch-Mediated Deviance Detection in Awake Rats. Front Psychiatry 2014; 5:96. [PMID: 25140157 PMCID: PMC4122188 DOI: 10.3389/fpsyt.2014.00096] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Accepted: 07/18/2014] [Indexed: 12/12/2022] Open
Abstract
Schizophrenia patients exhibit a decreased ability to detect change in their auditory environment as measured by auditory event-related potentials (ERP) such as mismatch negativity. This deficit has been linked to abnormal NMDA neurotransmission since, among other observations, non-selective channel blockers of NMDA reliably diminish automatic deviance detection in human subjects as well as in animal models. Recent molecular and functional evidence links NR2B receptor subtype to aberrant NMDA transmission in schizophrenia. However, it is unknown if NR2B receptors participate in pre-attentive deviance detection. We recorded ERP from the vertex of freely behaving rats in response to frequency mismatch protocols. We saw a robust increase in N1 response to deviants compared to standard as well as control stimuli indicating true deviance detection. Moreover, the increased negativity was highly sensitive to deviant probability. Next, we tested the effect of a non-selective NMDA channel blocker (ketamine, 30 mg/kg) and a highly selective NR2B antagonist, CP-101,606 (10 or 30 mg/kg) on deviance detection. Ketamine attenuated deviance mainly by increasing the amplitude of the standard ERP. Amplitude and/or latency of several ERP components were also markedly affected. In contrast, CP-101,606 robustly and dose-dependently inhibited the deviant's N1 amplitude, and as a consequence, completely abolished deviance detection. No other ERPs or components were affected. Thus, we report first evidence that NR2B receptors robustly participate in processes of automatic deviance detection in a rodent model. Lastly, our model demonstrates a path forward to test specific pharmacological hypotheses using translational endpoints relevant to aberrant sensory processing in schizophrenia.
Collapse
Affiliation(s)
- Digavalli V Sivarao
- Exploratory Biology and Genomics, Bristol Myers Squibb Company , Wallingford, CT , USA
| | - Ping Chen
- Exploratory Biology and Genomics, Bristol Myers Squibb Company , Wallingford, CT , USA
| | - Yili Yang
- Exploratory Biology and Genomics, Bristol Myers Squibb Company , Wallingford, CT , USA
| | - Yu-Wen Li
- Exploratory Biology and Genomics, Bristol Myers Squibb Company , Wallingford, CT , USA
| | - Rick Pieschl
- Exploratory Biology and Genomics, Bristol Myers Squibb Company , Wallingford, CT , USA
| | - Michael K Ahlijanian
- Exploratory Biology and Genomics, Bristol Myers Squibb Company , Wallingford, CT , USA
| |
Collapse
|
54
|
Ambrosi G, Cerri S, Blandini F. A further update on the role of excitotoxicity in the pathogenesis of Parkinson’s disease. J Neural Transm (Vienna) 2014; 121:849-59. [DOI: 10.1007/s00702-013-1149-z] [Citation(s) in RCA: 131] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 12/19/2013] [Indexed: 11/30/2022]
|
55
|
Rossi F, Marabese I, De Chiaro M, Boccella S, Luongo L, Guida F, De Gregorio D, Giordano C, de Novellis V, Palazzo E, Maione S. Dorsal striatum metabotropic glutamate receptor 8 affects nocifensive responses and rostral ventromedial medulla cell activity in neuropathic pain conditions. J Neurophysiol 2013; 111:2196-209. [PMID: 24304862 DOI: 10.1152/jn.00212.2013] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The present study investigated the role of metabotropic glutamate receptor subtype 8 (mGluR8) in the dorsal striatum (DS) in modulating thermonociception and rostral ventromedial medulla (RVM) ON and OFF cell activities in conditions of neuropathic pain induced by spared nerve injury (SNI) of the sciatic nerve in rats. The role of DS mGluR8 on mechanical allodynia was also investigated. Intra-DS (S)-3,4-dicarboxyphenylglycine [(S)-3,4-DCPG], a selective mGluR8 agonist, did not modify the activity of the ON and OFF cells in sham-operated rats. In SNI rats, which showed a reduction of the mechanical withdrawal threshold, intra-DS microinjection of (S)-3,4-DCPG inhibited the ongoing and tail flick-evoked activity of the ON cells while increasing the activity of the OFF cells. AZ12216052, a selective mGluR8 positive allosteric modulator (PAM), behaved like (S)-3,4-DCPG in increasing tail flick latency and OFF cell activity and decreasing ON cell activity in SNI rats only but was less potent. VU0155041, a selective mGluR4 PAM, was ineffective in changing thermal nociception and ON and OFF cell activity in both sham-operated and SNI rats. (S)-3,4-DCPG did not change mechanical withdrawal threshold in sham-operated rats but increased it in SNI rats. Furthermore, a decreased level of mGluR8 gene and immunoreactivity, expressed on GABAergic terminals, associated with a protein increase was found in the DS of SNI rats. These results suggest that stimulation of mGluR8 inhibits thermoceptive responses and mechanical allodynia. These effects were associated with inhibition of ON cells and stimulation of OFF cells within RVM.
Collapse
Affiliation(s)
- Francesca Rossi
- Department of Woman, Child and Specialist Surgery, The Second University of Naples, Naples, Italy
| | - Ida Marabese
- Department of Experimental Medicine, Pharmacology Division, The Second University of Naples, Naples, Italy; and
| | - Maria De Chiaro
- Department of Experimental Medicine, Pharmacology Division, The Second University of Naples, Naples, Italy; and
| | - Serena Boccella
- Department of Experimental Medicine, Pharmacology Division, The Second University of Naples, Naples, Italy; and
| | - Livio Luongo
- Department of Experimental Medicine, Pharmacology Division, The Second University of Naples, Naples, Italy; and
| | - Francesca Guida
- Department of Experimental Medicine, Pharmacology Division, The Second University of Naples, Naples, Italy; and
| | - Danilo De Gregorio
- Department of Experimental Medicine, Pharmacology Division, The Second University of Naples, Naples, Italy; and
| | - Catia Giordano
- Department of Experimental Medicine, Pharmacology Division, The Second University of Naples, Naples, Italy; and
| | - Vito de Novellis
- Department of Experimental Medicine, Pharmacology Division, The Second University of Naples, Naples, Italy; and
| | - Enza Palazzo
- Department of Anesthesiology, Surgery and Emergency, The Second University of Naples, Naples, Italy
| | - Sabatino Maione
- Department of Experimental Medicine, Pharmacology Division, The Second University of Naples, Naples, Italy; and
| |
Collapse
|
56
|
Andreoli V, De Marco EV, Trecroci F, Cittadella R, Di Palma G, Gambardella A. Potential involvement of GRIN2B encoding the NMDA receptor subunit NR2B in the spectrum of Alzheimer's disease. J Neural Transm (Vienna) 2013; 121:533-42. [PMID: 24292895 DOI: 10.1007/s00702-013-1125-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 11/19/2013] [Indexed: 12/15/2022]
Abstract
Increasing evidence links dysregulation of NR2B-containing N-methyl-D-aspartate receptor remodelling and trafficking to Alzheimer's disease (AD). This theme offers the possibility that the GRIN2B gene, encoding this selective NR2B subunit, represents a potential molecular modulating factor for this disease. Based on this hypothesis, we carried out a mutation scanning of exons and flanking regions of GRIN2B in a well-characterized cohort of AD patients, recruited from Southern Italy. A "de novo" p.K1293R mutation, affecting a highly conserved residue of the protein in the C-terminal domain, was observed for the first time in a woman with familial AD, as the only genetic alteration of relevance. Moreover, an association study between the other detected sequence variants and AD was performed. In particular, the study was focused on five identified single nucleotide polymorphisms: rs7301328, rs1805482, rs3026160, rs1806191 and rs1806201, highlighting a significant contribution from the GRIN2B rs1806201 T allele towards disease susceptibility [adjusted odds ratio (OR) = 1.92, 95% confidence interval (CI) 1.40-2.63, p < 0.001, after correction for sex, age, and APOE ε4 genotype]. This was confirmed by haplotype analysis that identified a specific haplotype, carrying the rs1806201 T allele (CCCTC), over-represented in patients versus controls (adjusted OR = 6.03; p < 0.0001). Although the pathogenic role of the GRIN2B-K1293R mutation in AD is not clear, our data advocate that genetic variability in the GRIN2B gene, involved in synaptic functioning, might provide valuable insights into disease pathogenesis, continuing to attract significant attention in biomedical research on its genetic and functional role.
Collapse
Affiliation(s)
- Virginia Andreoli
- Institute of Neurological Sciences, National Research Council, Pianolago di Mangone, Cosenza, Italy,
| | | | | | | | | | | |
Collapse
|
57
|
Liang W, Lam WP, Tang HC, Leung PC, Yew DT. Current Evidence of Chinese Herbal Constituents with Effects on NMDA Receptor Blockade. Pharmaceuticals (Basel) 2013; 6:1039-54. [PMID: 24276380 PMCID: PMC3817734 DOI: 10.3390/ph6081039] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Revised: 08/06/2013] [Accepted: 08/19/2013] [Indexed: 11/17/2022] Open
Abstract
NMDA receptor (NMDA-R) is an important molecular entity governing a wide range of functions in the central nervous system. For example, the NMDA-R is involved in memory and cognition, and impairment of both (as in Alzheimer's Disease) is attributed to NMDA-mediated neurotoxicity. With greater understanding of the NMDA-R structure, antagonists with varying degrees of binding-site and subtype selectivity have been developed and put into clinical use. Discovery of target-specific Chinese herbs have also been made in parallel. This article provides an overview of the known active sites on the NMDA-R, followed by a discussion of the relevant herbs and their constituents. Experimental evidence supporting the inhibitory role of the herbal compounds on the NMDA-R is highlighted. For some of the compounds, potential research directions are also proposed to further elucidate the underlying mechanisms of the herbs. It is envisaged that future investigations based on the present data will allow more clinically relevant herbs to be identified.
Collapse
Affiliation(s)
- Willmann Liang
- Institute of Chinese Medicine, The Chinese University of Hong Kong, Hong Kong; E-Mails: (W.P.L.); (H.C.T.); (P.C.L.)
| | | | | | | | - David T. Yew
- Institute of Chinese Medicine, The Chinese University of Hong Kong, Hong Kong; E-Mails: (W.P.L.); (H.C.T.); (P.C.L.)
| |
Collapse
|
58
|
Sączewski F, Balewski Ł. Biological activities of guanidine compounds, 2008 - 2012 update. Expert Opin Ther Pat 2013; 23:965-95. [PMID: 23617396 DOI: 10.1517/13543776.2013.788645] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Compounds incorporating guanidine moiety have found many practical applications in diverse areas of chemistry, such as nucleophilic organocatalysis, anion recognition and coordination chemistry. Moreover, guanidine functional group is found in natural products, pharmaceuticals and cosmetic ingredients produced by synthetic methods. Thus, knowledge of their biological activities and therapeutic uses is of utmost importance for researchers involved in drug discovery processes. AREAS COVERED In this review the authors highlight the continued development and therapeutic applications of newly synthesized guanidine-containing compounds including small peptides and peptidomimetics incorporating arginine. The review presents patents and patent applications filed in the years 2008 - 2012 with emphasis placed on new mechanisms of pharmacological action of guanidine derivatives. EXPERT OPINION While guanidines are often thought of as strong organic bases and compounds hydrophilic in nature, over the last 4 years there has been an enormous increase in discovery of new promising lead structures with guanidine core, suitable for development of potential drugs acting at central nervous system, anti-inflammatory agents, anti-diabetic and chemotherapeutic agents as well as cosmetics.
Collapse
Affiliation(s)
- Franciszek Sączewski
- Medical University of Gdańsk, Department of Chemical Technology of Drugs, Al. Gen. Hallera 107, 80-416 Gdańsk, Poland.
| | | |
Collapse
|