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Abstract
Alzheimer's disease is a progressive neurodegenerative disease for which no cure exists. There is a substantial need for new therapies that offer improved symptomatic benefit and disease-slowing capabilities. In recent decades there has been substantial progress in understanding the molecular and cellular changes associated with Alzheimer's disease pathology. This has resulted in identification of a large number of new drug targets. These targets include, but are not limited to, therapies that aim to prevent production of or remove the amyloid-beta protein that accumulates in neuritic plaques; to prevent the hyperphosphorylation and aggregation into paired helical filaments of the microtubule-associated protein tau; and to keep neurons alive and functioning normally in the face of these pathologic challenges. We provide a review of these targets for drug development.
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Affiliation(s)
- Joshua D Grill
- Mary S. Easton Center for Alzheimer's Disease Research, Deane F. Johnson Center for Neurotherapeutics, Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
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Parikh V, Ji J, Decker MW, Sarter M. Prefrontal beta2 subunit-containing and alpha7 nicotinic acetylcholine receptors differentially control glutamatergic and cholinergic signaling. J Neurosci 2010; 30:3518-30. [PMID: 20203212 PMCID: PMC2864641 DOI: 10.1523/jneurosci.5712-09.2010] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2009] [Revised: 01/17/2010] [Accepted: 01/22/2010] [Indexed: 11/21/2022] Open
Abstract
One-second-long increases in prefrontal cholinergic activity ("transients") were demonstrated previously to be necessary for the incorporation of cues into ongoing cognitive processes ("cue detection"). Nicotine and, more robustly, selective agonists at alpha4beta2* nicotinic acetylcholine receptors (nAChRs) enhance cue detection and attentional performance by augmenting prefrontal cholinergic activity. The present experiments determined the role of beta2-containing and alpha7 nAChRs in the generation of prefrontal cholinergic and glutamatergic transients in vivo. Transients were evoked by nicotine, the alpha4beta2* nAChR agonist ABT-089 [2-methyl-3-(2-(S)-pyrrolindinylmethoxy) pyridine dihydrochloride], or the alpha7 nAChR agonist A-582941 [2-methyl-5-(6-phenyl-pyridazin-3-yl)-octahydro-pyrrolo[3,4-c]pyrrole]. Transients were recorded in mice lacking beta2 or alpha7 nAChRs and in rats after removal of thalamic glutamatergic or midbrain dopaminergic inputs to prefrontal cortex. The main results indicate that stimulation of alpha4beta2* nAChRs evokes glutamate release and that the presence of thalamic afferents is necessary for the generation of cholinergic transients. ABT-089-evoked transients were completely abolished in mice lacking beta2* nAChRs. The amplitude, but not the decay rate, of nicotine-evoked transients was reduced by beta2* knock-out. Conversely, in mice lacking the alpha7 nAChR, the decay rate, but not the amplitude, of nicotine-evoked cholinergic and glutamatergic transients was attenuated. Substantiating the role of alpha7 nAChR in controlling the duration of release events, stimulation of alpha7 nAChR produced cholinergic transients that lasted 10- to 15-fold longer than those evoked by nicotine. alpha7 nAChR-evoked cholinergic transients are mediated in part by dopaminergic activity. Prefrontal alpha4beta2* nAChRs play a key role in evoking and facilitating the transient glutamatergic-cholinergic interactions that are necessary for cue detection and attentional performance.
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Affiliation(s)
- Vinay Parikh
- Department of Psychology and Neuroscience Program, University of Michigan, Ann Arbor, Michigan 48109-1043, and
| | - Jinzhao Ji
- Department of Psychology and Neuroscience Program, University of Michigan, Ann Arbor, Michigan 48109-1043, and
| | - Michael W. Decker
- Neuroscience Research, Abbott Laboratories, Abbott Park, Illinois 60064-6125
| | - Martin Sarter
- Department of Psychology and Neuroscience Program, University of Michigan, Ann Arbor, Michigan 48109-1043, and
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Nicotine improves AF64A-induced spatial memory deficits in Morris water maze in rats. Neurosci Lett 2010; 469:88-92. [DOI: 10.1016/j.neulet.2009.11.050] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2009] [Revised: 11/05/2009] [Accepted: 11/19/2009] [Indexed: 11/23/2022]
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54
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Nicotinic receptors: allosteric transitions and therapeutic targets in the nervous system. Nat Rev Drug Discov 2009; 8:733-50. [PMID: 19721446 DOI: 10.1038/nrd2927] [Citation(s) in RCA: 527] [Impact Index Per Article: 35.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Nicotinic receptors - a family of ligand-gated ion channels that mediate the effects of the neurotransmitter acetylcholine - are among the most well understood allosteric membrane proteins from a structural and functional perspective. There is also considerable interest in modulating nicotinic receptors to treat nervous-system disorders such as Alzheimer's disease, schizophrenia, depression, attention deficit hyperactivity disorder and tobacco addiction. This article describes both recent advances in our understanding of the assembly, activity and conformational transitions of nicotinic receptors, as well as developments in the therapeutic application of nicotinic receptor ligands, with the aim of aiding novel drug discovery by bridging the gap between these two rapidly developing fields.
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Rollema H, Hajós M, Seymour PA, Kozak R, Majchrzak MJ, Guanowsky V, Horner WE, Chapin DS, Hoffmann WE, Johnson DE, McLean S, Freeman J, Williams KE. Preclinical pharmacology of the alpha4beta2 nAChR partial agonist varenicline related to effects on reward, mood and cognition. Biochem Pharmacol 2009; 78:813-24. [PMID: 19501054 DOI: 10.1016/j.bcp.2009.05.033] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2009] [Revised: 05/23/2009] [Accepted: 05/26/2009] [Indexed: 12/12/2022]
Abstract
The pharmacological properties and pharmacokinetic profile of the alpha4beta2 nicotinic acetylcholine receptor (nAChR) partial agonist varenicline provide an advantageous combination of free brain levels and functional potencies at the target receptor that for a large part explain its efficacy as a smoking cessation aid. Since alpha4beta2 and other nAChR subtypes play important roles in mediating central processes that control reward, mood, cognition and attention, there is interest in examining the effects of selective nAChR ligands such as varenicline in preclinical animal models that assess these behaviors. Here we describe results from studies on varenicline's effects in animal models of addiction, depression, cognition and attention and discuss these in the context of recently published preclinical and preliminary clinical studies that collected data on varenicline's effects on mood, cognition and alcohol abuse disorder. Taken together, the preclinical and the limited clinical data show beneficial effects of varenicline, but further clinical studies are needed to evaluate whether the preclinical effects observed in animal models are translatable to the clinic.
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Affiliation(s)
- Hans Rollema
- Department of Neuroscience Biology, Pfizer Global Research and Development, Groton, CT 06340, USA.
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Potter AS, Ryan KK, Newhouse PA. Effects of acute ultra-low dose mecamylamine on cognition in adult attention-deficit/hyperactivity disorder (ADHD). Hum Psychopharmacol 2009; 24:309-17. [PMID: 19475630 PMCID: PMC2776071 DOI: 10.1002/hup.1026] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Nicotinic cholinergic stimulation has known beneficial effects in attention-deficit/hyperactivity disorder (ADHD). Mecamylamine is a non-competitive nicotinic antagonist which is reported in several animal studies to have paradoxical positive effects on cognition at ultra-low doses. Comparable studies in humans have not been conducted. The aim of this study was to determine the effects of acute ultra-low doses of mecamylamine on cognition in adult ADHD. METHODS Fifteen (6 female) non-smokers with ADHD completed this acute, within subjects, double blind study of 0.2, 0.5, 1.0 mg of oral mecamylamine and placebo. Behavioral inhibition, recognition memory, and delay aversion were assessed at each dose. RESULTS The 0.5 mg dose of mecamylamine significantly improved recognition memory and reduced tolerance for delay. Mecamylamine increased participant rated irritability and investigator rated restlessness. There were no effects on vital signs or physical side effects. CONCLUSION This is the first study to find measurable effects of ultra-low doses of mecamylamine in humans. Mecamylamine did not improve core ADHD cognitive symptoms, but significantly improved recognition memory. These effects may represent mixed receptor activity (activation and blockade) at the doses tested. The finding of beneficial effects on memory processes has important clinical implications and further exploration of this effect is warranted.
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Affiliation(s)
- Alexandra S. Potter
- Clinical Neuroscience Research Unit, Department of Psychiatry, College of Medicine, University of Vermont, Burlington, Vermont, USA,Correspondence to: Dr A. S. Potter, Clinical Neuroscience Research Unit, Department of Psychiatry, University of Vermont, South Prospect Street, Burlington, VT 05401, USA. Tel: 802-847-6955. Fax: 802-847-7889.
| | - Katherine K. Ryan
- Department of Psychology, University of Vermont, Burlington, Vermont, USA
| | - Paul A. Newhouse
- Clinical Neuroscience Research Unit, Department of Psychiatry, College of Medicine, University of Vermont, Burlington, Vermont, USA
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57
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Sarter M, Parikh V, Howe WM. nAChR agonist-induced cognition enhancement: integration of cognitive and neuronal mechanisms. Biochem Pharmacol 2009; 78:658-67. [PMID: 19406107 DOI: 10.1016/j.bcp.2009.04.019] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2009] [Revised: 04/14/2009] [Accepted: 04/16/2009] [Indexed: 01/04/2023]
Abstract
The identification and characterization of drugs for the treatment of cognitive disorders has been hampered by the absence of comprehensive hypotheses. Such hypotheses consist of (a) a precisely defined cognitive operation that fundamentally underlies a range of cognitive abilities and capacities and, if impaired, contributes to the manifestation of diverse cognitive symptoms; (b) defined neuronal mechanisms proposed to mediate the cognitive operation of interest; (c) evidence indicating that the putative cognition enhancer facilitates these neuronal mechanisms; (d) and evidence indicating that the cognition enhancer facilitates cognitive performance by modulating these underlying neuronal mechanisms. The evidence on the neuronal and attentional effects of nAChR agonists, specifically agonists selective for alpha4beta2* nAChRs, has begun to support such a hypothesis. nAChR agonists facilitate the detection of signals by augmenting the transient increases in prefrontal cholinergic activity that are necessary for a signal to gain control over behavior in attentional contexts. The prefrontal microcircuitry mediating these effects include alpha4beta2* nAChRs situated on the terminals of thalamic inputs and the glutamatergic stimulation of cholinergic terminals via ionotropic glutamate receptors. Collectively, this evidence forms the basis for hypothesis-guided development and characterization of cognition enhancers.
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Affiliation(s)
- Martin Sarter
- Department of Psychology and Neuroscience Program, University of Michigan, Ann Arbor, MI 48109-1043, USA.
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58
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Williams M, Martin Garraffo H, F. Spande T. Epibatidine: From Frog Alkaloid to Analgesic Clinical Candidates. A Testimonial to “True Grit”! HETEROCYCLES 2009. [DOI: 10.3987/rev-08-sr(d)5] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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59
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Becker RE, Greig NH, Giacobini E. Why do so many drugs for Alzheimer's disease fail in development? Time for new methods and new practices? J Alzheimers Dis 2008; 15:303-25. [PMID: 18953116 PMCID: PMC3372084 DOI: 10.3233/jad-2008-15213] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Alzheimer's disease (AD) drug developments and clinical trials (CT) remain vulnerable to problems that undermine research validity. Investigations of CT methods reveal how numerous factors decrease active drug-placebo group differences and increase variance, thereby reducing power to reach statistical significance for outcome measure differences in AD CTs. Such factors include, amongst many, inaccuracy, imprecision, bias, failures to follow or lack of operational protocols for applying CT methods, inter-site variance, and lack of homogeneous sampling using disorder criteria. After a review of the literature and survey of a sample of AD and Mild Cognitive Impairment (MCI) CTs, the authors question whether problems of human error preclude AD researchers from continuing their dependence on rated outcome measures for CTs. The authors propose that the realities of AD, especially a probable irreversible progression of neuropathology prior to onset of clinical symptoms or signs capable of differentiating persons at risk for AD from normal aged, require AD investigators and clinicians to privilege biomarkers and encourage their development as surrogate targets for preventive AD treatment developments, testing, and use in clinical practice.
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Affiliation(s)
- Robert E Becker
- Drug Design & Development Section, Laboratory of Neurosciences, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA.
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60
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Albrecht BK, Berry V, Boezio AA, Cao L, Clarkin K, Guo W, Harmange JC, Hierl M, Huang L, Janosky B, Knop J, Malmberg A, McDermott JS, Nguyen HQ, Springer SK, Waldon D, Woodin K, McDonough SI. Discovery and optimization of substituted piperidines as potent, selective, CNS-penetrant alpha4beta2 nicotinic acetylcholine receptor potentiators. Bioorg Med Chem Lett 2008; 18:5209-12. [PMID: 18789861 DOI: 10.1016/j.bmcl.2008.08.080] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2008] [Revised: 08/20/2008] [Accepted: 08/22/2008] [Indexed: 02/06/2023]
Abstract
The discovery of a series of small molecule alpha4beta2 nAChR potentiators is reported. The structure-activity relationship leads to potent compounds selective against nAChRs including alpha3beta2 and alpha3beta4 and optimized for CNS penetrance. Compounds increased currents through recombinant alpha4beta2 nAChRs, yet did not compete for binding with the orthosteric ligand cytisine. High potency and efficacy on the rat channel combined with good PK properties will allow testing of the alpha4beta2 potentiator mechanism in animal models of disease.
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Affiliation(s)
- Brian K Albrecht
- Department of Medicinal Chemistry, Amgen Inc., One Kendall Square, Building 1000, Cambridge, MA, USA.
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61
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Decker MW, Gopalakrishnan M, Meyer MD. The potential of neuronal nicotinic acetylcholine receptor agonists for treating CNS conditions. Expert Opin Drug Discov 2008; 3:1027-40. [DOI: 10.1517/17460441.3.9.1027] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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62
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Lendvai B, Vizi ES. Nonsynaptic Chemical Transmission Through Nicotinic Acetylcholine Receptors. Physiol Rev 2008; 88:333-49. [DOI: 10.1152/physrev.00040.2006] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
This review attempts to organize the different aspects of nicotinic transmission in the context of nonsynaptic interactions. Nicotinic acetylcholine receptors (nAChRs) dominantly operate in the nonsynaptic mode in the central nervous system despite their ligand-gated ion-channel nature, which would otherwise be better suited for fast synaptic transmission. This fast form of nonsynaptic transmission, most likely unique to nAChRs, represents a new avenue in the communication platforms of the brain. Cholinergic messages received by nAChRs, arriving at a later phase following synaptic activation, can interfere with dendritic signal integration. Nicotinic transmission plays a role in both neural plasticity and cellular learning processes, as well as in long-term changes in basic activity through fast activation, desensitization of receptors, and fluctuations of the steady-state levels of ACh. ACh release can contribute to plastic changes via activation of nAChRs in neurons and therefore plays a role in learning and memory in different brain regions. Assuming that nAChRs in human subjects are ready to receive long-lasting messages from the extracellular space because of their predominantly nonsynaptic distribution, they offer an ideal target for drug therapy at low, nontoxic drug levels.
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63
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Chapter 1 Cholinergic components of frontal lobe function and dysfunction. HANDBOOK OF CLINICAL NEUROLOGY 2008; 88:1-30. [DOI: 10.1016/s0072-9752(07)88001-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Conejero-Goldberg C, Davies P, Ulloa L. Alpha7 nicotinic acetylcholine receptor: a link between inflammation and neurodegeneration. Neurosci Biobehav Rev 2007; 32:693-706. [PMID: 18180036 DOI: 10.1016/j.neubiorev.2007.10.007] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2007] [Revised: 10/23/2007] [Accepted: 10/26/2007] [Indexed: 11/28/2022]
Abstract
Alzheimer's disease (AD) is the leading cause of dementia affecting over 25 million people worldwide. Classical studies focused on the description and characterization of the pathological hallmarks found in AD patients including the neurofibrillary tangles and the amyloid plaques. Current strategies focus on the etiology of these hallmarks and the different mechanisms contributing to neurodegeneration. Among them, recent studies reveal the close interplay between the immunological and the neurodegenerative processes. This article examines the implications of the alpha7 nicotinic acetylcholine receptor (alpha7nAChR) as a critical link between inflammation and neurodegeneration in AD. Alpha7nAChRs are not only expressed in neurons but also in Glia cells where they can modulate the immunological responses contributing to AD. Successful therapeutic strategies against AD should consider the connections between inflammation and neurodegeneration. Among them, alpha7nAChR may represent a pharmacological target to control these two mechanisms during the pathogenesis of neurodegenerative and behavioral disorders.
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Affiliation(s)
- Concepcion Conejero-Goldberg
- The Litwin-Zucker Research Center for the Study of Alzheimer's Disease, The Feinstein Institute for Medical Research, 350 Community Drive, Manhasset, NY 11030, USA.
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66
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Bitner RS, Bunnelle WH, Anderson DJ, Briggs CA, Buccafusco J, Curzon P, Decker MW, Frost JM, Gronlien JH, Gubbins E, Li J, Malysz J, Markosyan S, Marsh K, Meyer MD, Nikkel AL, Radek RJ, Robb HM, Timmermann D, Sullivan JP, Gopalakrishnan M. Broad-spectrum efficacy across cognitive domains by alpha7 nicotinic acetylcholine receptor agonism correlates with activation of ERK1/2 and CREB phosphorylation pathways. J Neurosci 2007; 27:10578-87. [PMID: 17898229 PMCID: PMC6673141 DOI: 10.1523/jneurosci.2444-07.2007] [Citation(s) in RCA: 157] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The alpha7 nicotinic acetylcholine receptor (nAChR) plays an important role in cognitive processes and may represent a drug target for treating cognitive deficits in neurodegenerative and psychiatric disorders. In the present study, we used a novel alpha7 nAChR-selective agonist, 2-methyl-5-(6-phenyl-pyridazin-3-yl)-octahydro-pyrrolo[3,4-c]pyrrole (A-582941) to interrogate cognitive efficacy, as well as examine potential cellular mechanisms of cognition. Exhibiting high affinity to native rat (Ki = 10.8 nM) and human (Ki = 16.7 nM) alpha7 nAChRs, A-582941 enhanced cognitive performance in behavioral assays including the monkey delayed matching-to-sample, rat social recognition, and mouse inhibitory avoidance models that capture domains of working memory, short-term recognition memory, and long-term memory consolidation, respectively. In addition, A-582941 normalized sensory gating deficits induced by the alpha7 nAChR antagonist methyllycaconitine in rats, and in DBA/2 mice that exhibit a natural sensory gating deficit. Examination of signaling pathways known to be involved in cognitive function revealed that alpha7 nAChR agonism increased extracellular-signal regulated kinase 1/2 (ERK1/2) phosphorylation in PC12 cells. Furthermore, increases in ERK1/2 and cAMP response element-binding protein (CREB) phosphorylation were observed in mouse cingulate cortex and/or hippocampus after acute A-582941 administration producing plasma concentrations in the range of alpha7 binding affinities and behavioral efficacious doses. The MEK inhibitor SL327 completely blocked alpha7 agonist-evoked ERK1/2 phosphorylation. Our results demonstrate that alpha7 nAChR agonism can lead to broad-spectrum efficacy in animal models at doses that enhance ERK1/2 and CREB phosphorylation/activation and may represent a mechanism that offers potential to improve cognitive deficits associated with neurodegenerative and psychiatric diseases, such as Alzheimer's disease and schizophrenia.
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Affiliation(s)
- Robert S Bitner
- Neuroscience Research, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, Illinois 60064, USA.
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67
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Wilens TE, Decker MW. Neuronal nicotinic receptor agonists for the treatment of attention-deficit/hyperactivity disorder: focus on cognition. Biochem Pharmacol 2007; 74:1212-23. [PMID: 17689498 PMCID: PMC2974320 DOI: 10.1016/j.bcp.2007.07.002] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2007] [Revised: 07/02/2007] [Accepted: 07/02/2007] [Indexed: 11/20/2022]
Abstract
Attention deficit/hyperactivity disorder (ADHD) is the most commonly diagnosed neurobehavioral disorder in children and adolescents, and in about half of these patients, significant symptomology continues into adulthood. Although impulsivity and hyperactivity are the most salient features of ADHD, cognitive deficits, particularly impairments in attention and executive function, are an important component, particularly in adolescents and adults, with over 90% of adults seeking treatment for ADHD manifesting cognitive dysfunction. Currently available medications treat the core ADHD symptoms but typically do not adequately address cognitive aspects of ADHD, underscoring the need for new therapeutics. Dopamine and norepinephrine are hypothesized to be particularly important in ADHD, but there is emerging evidence that cholinergic neurotransmission, particularly involving neuronal nicotinic acetylcholine receptors (nAChRs), may play a role in the pathophysiology of ADHD. Nicotine has demonstrated procognitive effects in both humans and experimental animals and has produced signals of efficacy in small proof-of-concept adult ADHD trials. Although adverse effects associated with nicotine preclude its development as a therapeutic, a number of novel nAChR agonists with improved safety/tolerability profiles have been discovered. Of these, ABT-418 and ABT-089 have both demonstrated signals of efficacy in adults with ADHD. Notably, tolerability issues that might be expected of a nAChR agonist, such as nausea and emesis, were not observed at efficacious doses of ABT-089. Further understanding of the effects of novel neuronal nAChR agonists on specific aspects of cognitive functioning in ADHD is required to assess the full potential of this approach.
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Affiliation(s)
- Timothy E. Wilens
- Massachusetts General Hospital, Pediatric Psychopharmacology Research Unit, Yawkey Center for Outpatient Care-YAW 6A, 55 Fruit St., Boston, MA 02114, Phone: 617-726-1731, Fax: 617-724-3742
| | - Michael W. Decker
- Neuroscience Drug Discovery, Global Pharmaceutical Research and Development, Abbott, Dept. R4N5; Bldg. AP-9A/3, 100 Abbott Park Rd. Abbott Park, IL 60064-6125, Phone: 1-847-937-2422, Fax: 1-847-937-9195
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Ji J, Schrimpf MR, Sippy KB, Bunnelle WH, Li T, Anderson DJ, Faltynek C, Surowy CS, Dyhring T, Ahring PK, Meyer MD. Synthesis and Structure−Activity Relationship Studies of 3,6-Diazabicyclo[3.2.0]heptanes as Novel α4β2 Nicotinic Acetylcholine Receptor Selective Agonists. J Med Chem 2007; 50:5493-508. [DOI: 10.1021/jm070755h] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Jianguo Ji
- Neuroscience Research, R47W, AP9A-1, Abbott, Abbott Park, Illinois 60064, and NeuroSearch A/S, Ballerup, Denmark
| | - Michael R. Schrimpf
- Neuroscience Research, R47W, AP9A-1, Abbott, Abbott Park, Illinois 60064, and NeuroSearch A/S, Ballerup, Denmark
| | - Kevin B. Sippy
- Neuroscience Research, R47W, AP9A-1, Abbott, Abbott Park, Illinois 60064, and NeuroSearch A/S, Ballerup, Denmark
| | - William H. Bunnelle
- Neuroscience Research, R47W, AP9A-1, Abbott, Abbott Park, Illinois 60064, and NeuroSearch A/S, Ballerup, Denmark
| | - Tao Li
- Neuroscience Research, R47W, AP9A-1, Abbott, Abbott Park, Illinois 60064, and NeuroSearch A/S, Ballerup, Denmark
| | - David J. Anderson
- Neuroscience Research, R47W, AP9A-1, Abbott, Abbott Park, Illinois 60064, and NeuroSearch A/S, Ballerup, Denmark
| | - Connie Faltynek
- Neuroscience Research, R47W, AP9A-1, Abbott, Abbott Park, Illinois 60064, and NeuroSearch A/S, Ballerup, Denmark
| | - Carol S. Surowy
- Neuroscience Research, R47W, AP9A-1, Abbott, Abbott Park, Illinois 60064, and NeuroSearch A/S, Ballerup, Denmark
| | - Tino Dyhring
- Neuroscience Research, R47W, AP9A-1, Abbott, Abbott Park, Illinois 60064, and NeuroSearch A/S, Ballerup, Denmark
| | - Philip K. Ahring
- Neuroscience Research, R47W, AP9A-1, Abbott, Abbott Park, Illinois 60064, and NeuroSearch A/S, Ballerup, Denmark
| | - Michael D. Meyer
- Neuroscience Research, R47W, AP9A-1, Abbott, Abbott Park, Illinois 60064, and NeuroSearch A/S, Ballerup, Denmark
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69
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Arneric SP, Holladay M, Williams M. Neuronal nicotinic receptors: A perspective on two decades of drug discovery research. Biochem Pharmacol 2007; 74:1092-101. [PMID: 17662959 DOI: 10.1016/j.bcp.2007.06.033] [Citation(s) in RCA: 168] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2007] [Revised: 06/19/2007] [Accepted: 06/20/2007] [Indexed: 11/19/2022]
Abstract
Neuronal nicotinic acetylcholine receptors (nAChRs) have been a target for drug discovery efforts, primarily for CNS indications, for the past two decades. While nicotine and related natural products have been used for smoking cessation in various formulations (e.g., gum, spray, patches), it was only in 2006 with the launch of varenicline (Chantix) by Pfizer for smoking cessation that a new chemical entity (NCE) originating from a rational medicinal chemistry effort targeting neuronal AChRs was approved. The current overview outlines the chronology of drug discovery efforts in nAChRs from the cloning of the receptor family in the 1980s, to initial research efforts at SIBIA, R.J. Reynolds and Abbott, to the current industry-wide interest in nAChR agonists as novel therapeutics for pain, schizophrenia and Alzheimer's Disease. Key events in the evolution of the nAChR field were the development of high throughput electrophysiological screening tools that provided the means to enable lead optimization efforts in medicinal chemistry and the discovery by John Daly at the NIH of the frog alkaloid, epibatidine, that provided the framework for the discovery of ABT-594, an alpha4beta2 agonist that is 200 times more potent than morphine as an analgesic. Over the next decade, it is anticipated that additional NCEs including antagonists and allosteric modulators (both positive and negative), interacting with various nAChR subtypes, will be advanced to the clinic in areas of high unmet medical need, e.g., pain, neurodegeneration, to provide novel medications with improved efficacy.
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70
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Ostrovskaya RU, Gruden MA, Bobkova NA, Sewell RDE, Gudasheva TA, Samokhin AN, Seredinin SB, Noppe W, Sherstnev VV, Morozova-Roche LA. The nootropic and neuroprotective proline-containing dipeptide noopept restores spatial memory and increases immunoreactivity to amyloid in an Alzheimer's disease model. J Psychopharmacol 2007; 21:611-9. [PMID: 17092975 DOI: 10.1177/0269881106071335] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The effects of the novel proline-containing nootropic and neuroprotective dipeptide, noopept (GVS-111, N-phenylacetyl-L-prolylglycine ethyl ester) were investigated in NMRI mice following olfactory bulbectomy. We have shown previously that these animals developed Alzheimer's disease (AD)-like behaviour, morphology and biochemistry including impairment of spatial memory, regional neuronal degeneration and elevated Abeta peptide brain levels. In the current investigation, spatial memory was assessed using the Morris water maze and serum antibodies to in vitro morphologically characterized amyloid structures of both Abeta((25-35)) peptide and equine lysozyme, as well as to neurotrophic glial factor S100b, were analyzed by enzyme-linked immunosorbent assay (ELISA). Noopept (administered at a dose of 0.01 mg/kg for a period of 21 days and during a further 5 days training) restored spatial memory and increased serum antibody levels to oligomers of Abeta((25-35)) peptide but not to equine lysozyme amyloid or S100b protein in bulbectomized animals. The positive immunotropic effect of noopept to Abeta((25-35)) peptide prefibrillar aggregates was more marked in sham-operated compared to the bulbectomized subjects which were characterized by an overall suppression of immunoreactivity. Enhancement of the immune response to Abeta((25-35)) peptide prefibrils caused by noopept may attenuate the neurotoxic consequences of amyloid fibrillization and also be associated with an improvement in spatial memory in bulbectomized mice. These actions of noopept, combined with its previously reported neuroprotective and cholinomimetic properties, suggests that this dipeptide may well be useful for improving cognitive deficits induced by neurodegenerative diseases.
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71
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Bunnelle WH, Daanen JF, Ryther KB, Schrimpf MR, Dart MJ, Gelain A, Meyer MD, Frost JM, Anderson DJ, Buckley M, Curzon P, Cao YJ, Puttfarcken P, Searle X, Ji J, Putman CB, Surowy C, Toma L, Barlocco D. Structure−Activity Studies and Analgesic Efficacy of N-(3-Pyridinyl)-Bridged Bicyclic Diamines, Exceptionally Potent Agonists at Nicotinic Acetylcholine Receptors. J Med Chem 2007; 50:3627-44. [PMID: 17585748 DOI: 10.1021/jm070018l] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A series of exceptionally potent agonists at neuronal nicotinic acetylcholine receptors (nAChRs) has been investigated. Several N-(3-pyridinyl) derivatives of bridged bicyclic diamines exhibit double-digit-picomolar binding affinities for the alpha 4 beta 2 subtype, placing them with epibatidine among the most potent nAChR ligands described to date. Structure-activity studies have revealed that substitutions, particularly hydrophilic groups in the pyridine 5-position, differentially modulate the agonist activity at ganglionic vs central nAChR subtypes, so that improved subtype selectivity can be demonstrated in vitro. Analgesic efficacy has been achieved across a broad range of pain states, including rodent models of acute thermal nociception, persistent pain, and neuropathic allodynia. Unfortunately, the hydrophilic pyridine substituents that were shown to enhance agonist selectivity for central nAChRs in vitro tend to limit CNS penetration in vivo, so that analgesic efficacy with an improved therapeutic window was not realized with those compounds.
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Affiliation(s)
- William H Bunnelle
- Neuroscience Research, Abbott Laboratories, Department R47W, Building AP9A, Abbott Park, Illinois 60064-6117, USA.
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72
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Pogocki D, Ruman T, Danilczuk M, Danilczuk M, Celuch M, Wałajtys-Rode E. Application of nicotine enantiomers, derivatives and analogues in therapy of neurodegenerative disorders. Eur J Pharmacol 2007; 563:18-39. [PMID: 17376429 DOI: 10.1016/j.ejphar.2007.02.038] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2007] [Revised: 02/04/2007] [Accepted: 02/15/2007] [Indexed: 12/21/2022]
Abstract
This review gives a brief overview over the major aspects of application of the nicotine alkaloid and its close derivatives in the therapy of some neurodegenerative disorders and diseases (e.g. Alzheimer's disease, Parkinson's disease, Tourette's syndrome, schizophrenia etc.). The issues concerning methods of nicotine analysis and isolation, and some molecular aspects of nicotine pharmacology are included. The natural and synthetic analogues of nicotine that are considered for medical practice are also mentioned. The molecular properties of two naturally occurring nicotine enantiomers are compared--the less-common but less-toxic (R)-nicotine is suggested as a natural compound that may find its place in pharmaceutical practice.
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Affiliation(s)
- Dariusz Pogocki
- Rzeszów University of Technology, Faculty of Chemistry, Department of Biochemistry and Biotechnology, 6 Powstańców Warszawy Ave. 35-959 Rzeszów, Poland
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73
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Dunbar G, Boeijinga PH, Demazières A, Cisterni C, Kuchibhatla R, Wesnes K, Luthringer R. Effects of TC-1734 (AZD3480), a selective neuronal nicotinic receptor agonist, on cognitive performance and the EEG of young healthy male volunteers. Psychopharmacology (Berl) 2007; 191:919-29. [PMID: 17225162 DOI: 10.1007/s00213-006-0675-x] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2006] [Accepted: 12/04/2006] [Indexed: 01/13/2023]
Abstract
OBJECTIVES The aim of this study was to get insight into the central effects of TC-1734 (renamed AZD3480), a selective agonist at the neuronal nicotinic receptor of the alpha4beta2 subtype. MATERIALS AND METHODS Electroencephalography (EEG) techniques and computerized cognitive tests were performed in young, healthy male volunteers during two double-blind and placebo-controlled studies: a rising single dose crossover study (from 2 to 320 mg) and a rising repeated dose study with a parallel group design (50, 100, and 200 mg). RESULTS In contrast to acute administration, administration of AZD3480 over 10 days produced statistically significant enhancement of several cognitive measures (attention and episodic memory) compared to placebo. Regarding EEG data, AZD3480 showed acceleration of the alpha centroid and of the alpha peak in the single-dose study. This EEG profile of the acceleration type was confirmed in the repeated dose study on both day 1 and day 10, with the greatest effect observed with the highest dose. The EEG pattern shown for AZD3480 was consistent with that previously described with other drugs known to improve attention and vigilance (including nicotine). In addition, subjects dosed with AZD3480 showed a statistically significant increase in mismatch negativity (MMN) amplitude at 50 and 200 mg while reducing MMN latency (200 mg only), suggesting an improvement of pre-attentional mechanisms. CONCLUSION These early data in healthy subjects provide encouragement to consider development of AZD3480 as a novel agent for the treatment of cognitive decline in the elderly, including age-associated memory impairment and/or dementia of the Alzheimer's type.
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Affiliation(s)
- G Dunbar
- TARGACEPT Inc., 200 East First Street Suite 300, Winston-Salem, NC 27101-4165, USA
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74
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Hu M, Schurdak ME, Puttfarcken PS, El Kouhen R, Gopalakrishnan M, Li J. High content screen microscopy analysis of A beta 1-42-induced neurite outgrowth reduction in rat primary cortical neurons: neuroprotective effects of alpha 7 neuronal nicotinic acetylcholine receptor ligands. Brain Res 2007; 1151:227-35. [PMID: 17449017 DOI: 10.1016/j.brainres.2007.03.051] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2007] [Revised: 03/05/2007] [Accepted: 03/06/2007] [Indexed: 12/14/2022]
Abstract
beta-Amyloid peptide 1-42 (A beta(1-42)) is generated from amyloid precursor protein (APP) and associated with neurodegeneration in Alzheimer's disease (AD). A beta(1-42) has been shown to be cytotoxic when incubated with cultured neurons. However, APP transgenic mice over-expressing A beta(1-42) do not show substantial loss of neurons, despite deficits in learning and memory. It is thus emerging that A beta(1-42)-induced memory deficits may involve subtler neuronal alternations leading to synaptic deficits, prior to frank neurodegeneration in AD brains. In this study, high content screen (HCS) microscopy, an advanced high-throughput cellular image processing and analysis technique, was utilized in establishing an in vitro model of A beta(1-42)-induced neurotoxicity utilizing rat neonatal primary cortical cells. Neurite outgrowth was found to be significantly reduced by A beta(1-42) (300 nM to 30 microM), but not by the scrambled control peptide control, in a time- and concentration-dependent manner. In contrast, no reduction in the total number of neurons was observed. The A beta(1-42)-induced reduction of neurite outgrowth was attenuated by the NMDA receptor antagonist memantine and the alpha 7 nicotinic acetylcholine receptor (nAChR) selective agonist PNU-282987. Interestingly, the alpha 7 nAChR antagonist methyllycaconitine also significantly prevented reduction in A beta(1-42)-induced neurite outgrowth. The observed neuroprotective effects could arise either from interference of A beta(1-42) interactions with alpha 7 nAChRs or by modification of receptor-mediated signaling pathways. Our studies demonstrate that reduction of neurite outgrowth may serve as a model representing A beta(1-42)-mediated neuritic and synaptic toxicity, which, in combination of HCS, provides a high-throughput cell-based assay that can be used to evaluate compounds with neuroprotective properties in neurons.
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Affiliation(s)
- Min Hu
- Neuroscience Research, Abbott Laboratories, 100 Abbott Park Road, Abbott Park, IL 60064-6125, USA
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75
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Dunbar GC, Kuchibhatla R. Cognitive enhancement in man with ispronicline, a nicotinic partial agonist. J Mol Neurosci 2007; 30:169-72. [PMID: 17192668 DOI: 10.1385/jmn:30:1:169] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/1999] [Revised: 11/30/1999] [Accepted: 11/30/1999] [Indexed: 11/11/2022]
Abstract
Cholinergic mechanisms are clearly involved in memory deficits associated with Alzheimer's disease (AD) (Perry et al., 1977). Recently, there has been growing interest in the nicotinic approach to the treatment of AD; however, compounds have failed in the clinic because of a lack of separation between central and peripheral nicotinic effects (Potter et al., 1999). Ispronicline (TC-1734) is an orally active, selective, partial agonist of the central alpha4beta2 neuronal nicotinic acetylcholine receptor (nAChR), with high binding affinity to membrane preparations from rat brain or mammalian cells expressing recombinant human alpha4beta2 receptor (Gatto et al., 2004). Ispronicline has no detectable effects on muscle or ganglionic nAChRs, indicating a marked CNS over PNS selectivity. In animal models ispronicline potently improved cognitive function. A long duration of memory enhancement was displayed in object recognition and radial arm maze tests. Ispronicline pharmacokinetics (half-life of 2 h in rats) contrasts with the long-lasting improvement of working memory (18 h to 2 d) (Gatto et al., 2004).
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76
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McClernon FJ, Hiott FB, Westman EC, Rose JE, Levin ED. Transdermal nicotine attenuates depression symptoms in nonsmokers: a double-blind, placebo-controlled trial. Psychopharmacology (Berl) 2006; 189:125-33. [PMID: 16977477 DOI: 10.1007/s00213-006-0516-y] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2006] [Accepted: 07/10/2006] [Indexed: 11/29/2022]
Abstract
RATIONALE Despite established links between nicotine dependence and depression, little research has examined the effects of nicotine on depression symptoms. OBJECTIVE This study evaluated the acute and chronic effects of transdermal nicotine in nonsmokers with baseline depression symptoms during a 4-week, double-blind, placebo-controlled trial. METHODS Nonsmokers with scores >or=10 on the Center for Epidemiological Studies Depression scale (CES-D) were recruited from the community. Mood and cognitive performance were measured at baseline (day 0) and at 1, 8, 21, and 28 days. Participants were randomly assigned to wear a placebo or nicotine patch for 4 weeks (3.5 mg/day during weeks 1 and 4; 7 mg/day during weeks 2 and 3). The final sample consisted of 11 nonsmokers with a mean baseline CES-D score of 27.36 (SD=10.53). RESULTS Salivary nicotine levels indicated the majority of participants were compliant with treatment. Acute nicotine did not alter mood. After adjusting for baseline values, chronic nicotine resulted in a significant decline in CES-D scores at day 8 (3.5 mg/day), but returned to placebo levels by the last visit. This return to baseline levels was coincident with a decrease in nicotine administration from 7 to 3.5 mg/day. A similar trend for improved response inhibition as measured by the Conners Continuous Performance Task was also observed. Reported side effects were infrequent and minimal. CONCLUSION These findings suggest a role for nicotinic receptor systems in the pathophysiology of depression and that nicotinic compounds should be evaluated for treating depression symptoms.
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Affiliation(s)
- F Joseph McClernon
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC, USA.
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77
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Kadir A, Almkvist O, Wall A, Långström B, Nordberg A. PET imaging of cortical 11C-nicotine binding correlates with the cognitive function of attention in Alzheimer's disease. Psychopharmacology (Berl) 2006; 188:509-20. [PMID: 16832659 DOI: 10.1007/s00213-006-0447-7] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2006] [Accepted: 05/24/2006] [Indexed: 10/24/2022]
Abstract
RATIONALE Patients suffering from Alzheimer's disease (AD) experience a marked reduction in cortical nicotinic acetylcholine receptors (nAChRs). In particular, selective loss of the alpha4beta2 nAChR subtype was observed in postmortem AD brain tissue. The alpha4 and alpha7 nAChR subunits were suggested to play an important role in cognitive function. Positron emission tomography (PET) has so far been used to visualize neuronal nAChRs in vivo by 11C-nicotine binding. OBJECTIVES To investigate the relationship between measures of cognitive function and in vivo 11C-nicotine binding in mild AD brain as assessed by PET. MATERIALS AND METHODS Twenty-seven patients with mild AD were recruited in this study. A dual tracer model with administration of 15O-water for regional cerebral blood flow and (S)(-)11C-nicotine was used to assess nicotine binding sites in the brain by PET. Cognitive function was assessed using neuropsychological tests of global cognition, episodic memory, attention, and visuospatial ability. RESULTS Mean cortical 11C-nicotine binding significantly correlated with the results of attention tests [Digit Symbol test (r = -0.44 and p = 0.02) and Trail Making Test A (TMT-A) (r = 0.42 and p = 0.03)]. No significant correlation was observed between 11C-nicotine binding and the results of tests of episodic memory or visuospatial ability. Regional analysis showed that 11C-nicotine binding in the frontal and parietal cortex, which are the main areas for attention, correlated significantly with the Digit Symbol test and TMT-A results. CONCLUSION Cortical nicotinic receptors in vivo in mild AD patients are robustly associated with the cognitive function of attention.
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Affiliation(s)
- Ahmadul Kadir
- Department of Neurobiology, Care Sciences and Society, Division of Molecular Neuropharmacology, Karolinska Institutet, Karolinska University Hospital Huddinge, Novum Floor-5, Stockholm, 141 86, Sweden
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78
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Ceballos NA. Tobacco Use, Alcohol Dependence, and Cognitive Performance. The Journal of General Psychology 2006; 133:375-88. [PMID: 17128957 DOI: 10.3200/genp.133.4.375-388] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Chronic alcohol abuse has long been associated with a mild, generalized pattern of cognitive decrements. However, it is important to note that problem drinking rarely occurs in isolation from abuse of other drugs. For people dependent upon alcohol, tobacco is one of the mostly commonly coabused substances. Recent research suggests that individuals with alcohol dependency may gravitate toward tobacco use, in part, because of the positive effects of nicotine on aspects of cognitive performance that may be compromised as a consequence of chronic alcohol misuse. In this article, the author focuses on the effects of nicotine on behavioral and electrophysiological indexes of cognitive performance, and the impact of these effects on alcohol-related cognitive decrements. The author discusses implications of these findings in the context of treatment and recovery of people with alcoholism.
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Affiliation(s)
- Natalie A Ceballos
- Department of Psychology, Texas State University, San Marcos, Texas 78666, USA.
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79
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Sarter M. Preclinical research into cognition enhancers. Trends Pharmacol Sci 2006; 27:602-8. [PMID: 16997388 DOI: 10.1016/j.tips.2006.09.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2006] [Revised: 08/16/2006] [Accepted: 09/12/2006] [Indexed: 10/24/2022]
Abstract
The preclinical development of drugs to treat the cognitive symptoms of neuropsychiatric and neurological disorders is a formidable challenge. Evidence from a wide range of preclinical behavioral and neuropharmacological tests has formed the basis for predicting drug-induced cognition enhancement in normal volunteers and in patients with cognitive impairments. However, the limited validity of preclinical predictions of this enhancement in humans indicates that conventional screening for "broadly active" compounds represents a below-optimal research strategy. This article conceptualizes the evidence needed to improve the predictive validity of preclinical research designed to discover and characterize cognition enhancers. We suggest that the investigation of reciprocal relationships among molecular, cellular, behavioral and cognitive processes modulated by candidate drugs represents the core of such research. By contrast, the usefulness of simple and high-throughput screening tests for the detection of cognition enhancers might be restricted to advanced drug-finding programs that are guided by evidence of the modulation of neurocognitive relationships by cognition enhancers and that are informed by iterative preclinical-clinical cross-validation of research approaches. We stress the need for basic biopsychological research approaches in preclinical programs to find and characterize drugs to treat cognitive disorders.
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Affiliation(s)
- Martin Sarter
- Department of Psychology, University of Michigan, 4032 East Hall, 530 Church Street, Ann Arbor, MI 48109-1043, USA.
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80
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Levin ED, McClernon FJ, Rezvani AH. Nicotinic effects on cognitive function: behavioral characterization, pharmacological specification, and anatomic localization. Psychopharmacology (Berl) 2006; 184:523-39. [PMID: 16220335 DOI: 10.1007/s00213-005-0164-7] [Citation(s) in RCA: 590] [Impact Index Per Article: 32.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2005] [Accepted: 08/06/2005] [Indexed: 10/25/2022]
Abstract
RATIONALE Nicotine has been shown in a variety of studies in humans and experimental animals to improve cognitive function. Nicotinic treatments are being developed as therapeutic treatments for cognitive dysfunction. OBJECTIVES Critical for the development of nicotinic therapeutics is an understanding of the neurobehavioral bases for nicotinic involvement in cognitive function. METHODS Specific and diverse cognitive functions affected by nicotinic treatments are reviewed, including attention, learning, and memory. The neural substrates for these behavioral actions involve the identification of the critical pharmacologic receptor targets, in particular brain locations, and how those incipient targets integrate with broader neural systems involved with cognitive function. RESULTS Nicotine and nicotinic agonists can improve working memory function, learning, and attention. Both alpha4beta2 and alpha7 nicotinic receptors appear to be critical for memory function. The hippocampus and the amygdala in particular have been found to be important for memory, with decreased nicotinic activity in these areas impairing memory. Nicotine and nicotinic analogs have shown promise for inducing cognitive improvement. Positive therapeutic effects have been seen in initial studies with a variety of cognitive dysfunctions, including Alzheimer's disease, age-associated memory impairment, schizophrenia, and attention deficit hyperactivity disorder. CONCLUSIONS Discovery of the behavioral, pharmacological, and anatomic specificity of nicotinic effects on learning, memory, and attention not only aids the understanding of nicotinic involvement in the basis of cognitive function, but also helps in the development of novel nicotinic treatments for cognitive dysfunction. Nicotinic treatments directed at specific receptor subtypes and nicotinic cotreatments with drugs affecting interacting transmitter systems may provide cognitive benefits most relevant to different syndromes of cognitive impairment such as Alzheimer's disease, schizophrenia, and attention deficit hyperactivity disorder. Further research is necessary in order to determine the efficacy and safety of nicotinic treatments of these cognitive disorders.
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Affiliation(s)
- Edward D Levin
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Box #3412, Durham, NC 27710, USA.
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81
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Sharifzadeh M, Tavasoli M, Naghdi N, Ghanbari A, Amini M, Roghani A. Post-training intrahippocampal infusion of nicotine prevents spatial memory retention deficits induced by the cyclo-oxygenase-2-specific inhibitor celecoxib in rats. J Neurochem 2005; 95:1078-90. [PMID: 16150053 DOI: 10.1111/j.1471-4159.2005.03454.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Recently, we demonstrated that intrahippocampal infusion of the cyclo-oxygenase (COX)-2-specific inhibitor celecoxib impaired spatial memory retention in the Morris water maze. In the present work, we investigated the effects of nicotine, infused in the rat dorsal hippocampus several minutes after infusion of celecoxib, on memory retention in the Morris water maze. Rats were trained for 3 days; each day included two blocks, and each block contained four trials. Test trials were conducted 48 h after surgery. As expected, bilateral intrahippocampal infusion of celecoxib (19 microg/side; 0.1 m) increased escape latency and travel distance in rats, indicating significant impairment of spatial memory retention. We also examined the effects of bilateral infusion of nicotine (0.5, 1.0 and 2.0 microg/side) on memory retention. Infusion of 1 microg nicotine significantly decreased escape latency and travel distance but not swimming speed, compared with controls, suggesting memory retention enhancement by nicotine at this concentration. In separate experiments, bilateral infusion of nicotine, infused 5 min after 0.1 m (19 microg/side) celecoxib infusion, was associated with escape latency, travel distance and swimming speed profiles very similar to those in control animals. Brain tissue sections from several of these animals were subjected to immunohistochemical staining analysis with anti-COX-2 antibodies. Quantification analysis by optical density measurements showed that the celecoxib infusion reduced the immunoreactivity of COX-2-containing neurons in the CA1 area of the hippocampus compared with controls, although this reduction was not significant. However, infusion of a combination of celecoxib and nicotine significantly increased this immunoreactivity compared with levels in control and celecoxib-infused groups. These results suggest that nicotine prevented or reversed the adverse effects of celecoxib on spatial memory retention and protected or restored the immunostaining pattern of COX-2 neurons in the rat dorsal hippocampus.
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Affiliation(s)
- Mohammad Sharifzadeh
- Department of Toxicology and Pharmacology, School of Pharmacy, Pharmaceutical Sciences and Medicinal Plant Research Centers, University of Medical Sciences, Tehran, Iran.
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82
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Sacco KA, Bannon KL, George TP. Nicotinic receptor mechanisms and cognition in normal states and neuropsychiatric disorders. J Psychopharmacol 2005. [PMID: 15582913 DOI: 10.1177/0269881104047273] [Citation(s) in RCA: 161] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Cigarette smoking rates in the American population are approximately 23%, whereas rates of smoking in clinical and population studies of individuals with neuropsychiatric disorders are typically two- to four-fold higher. Studies conducted in a variety of neuropsychiatric populations [e.g. attention-deficit hyperactivity disorder (ADHD), Alzheimer's disease, schizophrenia] have collectively suggested that nicotine may be efficacious in remediating selected cognitive deficits associated with these disorders, thus providing a framework for understanding the specific vulnerability of these patients to smoking initiation and maintenance. However, the specific gain in cognitive performance produced by nicotine administration in healthy subjects with normal cognitive function is less clear. This article reviews our current understanding of central nicotinic acetylcholine receptor (nAChRs) systems in normal and neuropsychiatric disease states and, specifically, their role with respect to cognitive dysfunction and clinical symptoms in several specific neuropsychiatric populations, including ADHD, Alzheimer's disease, Parkinson's disease, Tourette's Disorder, schizophrenia and affective disorders. The potential benefits of nicotinic agents for therapeutic use in neuropsychiatric disorders is discussed, as well as directions for further research in this area.
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Affiliation(s)
- Kristi A Sacco
- Program for Research in Smokers with Mental Illness, Division of Substance Abuse, Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06519, USA.
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83
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Chang KA, Suh YH. Pathophysiological roles of amyloidogenic carboxy-terminal fragments of the beta-amyloid precursor protein in Alzheimer's disease. J Pharmacol Sci 2005; 97:461-71. [PMID: 15821343 DOI: 10.1254/jphs.cr0050014] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Several lines of evidence suggest that some of the neurotoxicity in Alzheimer's disease (AD) is attributed to proteolytic fragments of amyloid precursor protein (APP) and beta-amyloid (Abeta) may not be the sole active component involved in the pathogenesis of AD. The potential effects of other cleavage products of APP need to be explored. The CTFs, carboxy-terminal fragments of APP, have been found in AD patients' brain and reported to exhibit much higher neurotoxicity in a variety of preparations than Abeta. Furthermore CTFs are known to impair calcium homeostasis and learning and memory through blocking LTP, triggering a strong inflammatory reaction through MAPKs- and NF-kappaB-dependent astrocytosis and iNOS induction. Recently, it was reported that CTF translocated into the nucleus, binding with Fe65 and CP2, and in turn, affected transcription of genes including glycogen synthase kinase-3beta, which results in the induction of tau-rich neurofibrillary tangles and subsequently cell death. Spatial memory of transgenic (Tg) mice overexpressing CT100 was significantly impaired and CTFs were detected in the neurons as well as in plaques of the Tg mice and double Tg mice carrying CT100 and mutant tau. In this review, we summarize observations indicating that both CTF and Abeta may participate in the neuronal degeneration in the progress of AD by differential mechanisms.
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Affiliation(s)
- Keun-A Chang
- Department of Pharmacology, College of Medicine, National Creative Research Initiative Center for Alzheimer's Dementia and Neuroscience Research Institute, MRC, Seoul National University, Korea
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84
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Sacco KA, Bannon KL, George TP. Nicotinic receptor mechanisms and cognition in normal states and neuropsychiatric disorders. J Psychopharmacol 2004; 18:457-74. [PMID: 15582913 PMCID: PMC1201375 DOI: 10.1177/026988110401800403] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Cigarette smoking rates in the American population are approximately 23%, whereas rates of smoking in clinical and population studies of individuals with neuropsychiatric disorders are typically two- to four-fold higher. Studies conducted in a variety of neuropsychiatric populations [e.g. attention-deficit hyperactivity disorder (ADHD), Alzheimer's disease, schizophrenia] have collectively suggested that nicotine may be efficacious in remediating selected cognitive deficits associated with these disorders, thus providing a framework for understanding the specific vulnerability of these patients to smoking initiation and maintenance. However, the specific gain in cognitive performance produced by nicotine administration in healthy subjects with normal cognitive function is less clear. This article reviews our current understanding of central nicotinic acetylcholine receptor (nAChRs) systems in normal and neuropsychiatric disease states and, specifically, their role with respect to cognitive dysfunction and clinical symptoms in several specific neuropsychiatric populations, including ADHD, Alzheimer's disease, Parkinson's disease, Tourette's Disorder, schizophrenia and affective disorders. The potential benefits of nicotinic agents for therapeutic use in neuropsychiatric disorders is discussed, as well as directions for further research in this area.
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Affiliation(s)
- Kristi A Sacco
- Program for Research in Smokers with Mental Illness, Division of Substance Abuse, Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06519, USA.
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85
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Potter AS, Newhouse PA. Effects of acute nicotine administration on behavioral inhibition in adolescents with attention-deficit/hyperactivity disorder. Psychopharmacology (Berl) 2004; 176:182-94. [PMID: 15083253 DOI: 10.1007/s00213-004-1874-y] [Citation(s) in RCA: 133] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2003] [Accepted: 03/09/2004] [Indexed: 10/26/2022]
Abstract
RATIONALE Adolescents with attention-deficit/hyperactivity disorder (ADHD) become cigarette smokers at twice the rate of non-ADHD adolescents, and this finding continues into adulthood. Abnormal cognitive/behavioral inhibition is one core cognitive symptom of ADHD, leading to impulsive behavior in people with this disorder. Nicotine, contained in tobacco smoke, is known to improve attention, vigilance, and short-term memory. However, little is known about how nicotine might effect cognitive/behavioral inhibition. OBJECTIVE This study tested the hypothesis that acute nicotine administration would improve cognitive/behavioral inhibition in non-smoking adolescents with ADHD. METHODS This single-dose, acute, repeated-measures, double blind study in adolescents (13-17 years) with DSM-IV confirmed ADHD assessed the effects of transdermal nicotine, oral methylphenidate, and placebo on inhibition in non-smoking adolescents with ADHD. Dependent measures included tests of cognitive/behavioral inhibition (the stop signal task), cognitive interference control (the Stroop task), and a measure of verbal learning and recognition (the hi-low imagery task). RESULTS Results from five subjects indicated that stop signal reaction time (SSRT), an estimate of the speed of inhibiting a response, was significantly (P<0.01) improved following both nicotine and methylphenidate treatment as compared to placebo treatment. Neither "go" reaction time nor accuracy showed any effect of drug. In the Stroop task, another task of cognitive inhibition, nicotine but not methylphenidate significantly (P<0.05) decreased the Stroop effect compared to placebo. CONCLUSIONS These results indicate that nicotine administration has measurable positive effects on cognitive/behavioral inhibition in adolescents with ADHD. The size of the effect is at least comparable to methylphenidate. Positive effects of nicotine on inhibitional performance may contribute to higher rates of cigarette use in adolescents with ADHD.
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Affiliation(s)
- Alexandra S Potter
- Clinical Neuroscience Research Unit, Department of Psychiatry, College of Medicine, University of Vermont, 1 South Prospect Street, Burlington, VT 05401, USA
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86
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Katner SN, Davis SA, Kirsten AJ, Taffe MA. Effects of nicotine and mecamylamine on cognition in rhesus monkeys. Psychopharmacology (Berl) 2004; 175:225-40. [PMID: 15112030 PMCID: PMC2121304 DOI: 10.1007/s00213-004-1804-z] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2003] [Accepted: 01/11/2004] [Indexed: 10/26/2022]
Abstract
RATIONALE Nicotine and other agonists of nicotinic cholinergic receptors (nAChR) have been shown to improve performance in specific memory domains in rodents and monkeys. Such beneficial effects are observed in preclinical models of age-related cognitive decline, stimulating interest in nAChR ligands as possible therapeutics. Prior work has typically focused on assays of spatial working memory in rodent studies and visual recognition memory in monkey studies. OBJECTIVE The current study was conducted to determine the role played by nAChRs in multiple types of memory in monkeys. METHODS Rhesus monkeys (n=6) were trained to perform a battery of six behavioral tasks and then serially challenged with acute doses of nicotine (3.2-56 microg/kg, i.m.) and the nAChR antagonist mecamylamine (0.32-1.78 mg/kg, i.m.). RESULTS Nicotine improved performance on tests designed to assay visual recognition memory, spatial working memory and visuo-spatial associative memory, while mecamylamine impaired visuo-spatial associative memory. Ballistic and fine motor performance was not significantly improved by nicotine but fine motor performance was impaired by mecamylamine. CONCLUSIONS Although nicotine may improve performance in multiple domains, effects on visuo-spatial associative memory is the most specifically attributable to nAChR signaling.
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Affiliation(s)
- Simon N Katner
- Department of Neuropharmacology, CVN-7, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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Wilkinson DG, Francis PT, Schwam E, Payne-Parrish J. Cholinesterase inhibitors used in the treatment of Alzheimer's disease: the relationship between pharmacological effects and clinical efficacy. Drugs Aging 2004; 21:453-78. [PMID: 15132713 DOI: 10.2165/00002512-200421070-00004] [Citation(s) in RCA: 220] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The deficiency in cholinergic neurotransmission in Alzheimer's disease has led to the development of cholinesterase inhibitors as the first-line treatment for symptoms of this disease. The clinical benefits of these agents include improvements, stabilisation or less than expected decline in cognition, function and behaviour. The common mechanism of action underlying this class of agents is an increase in available acetylcholine through inhibition of the catabolic enzyme, acetylcholinesterase. There is substantial evidence that the cholinesterase inhibitors, including donepezil, galantamine and rivastigmine, decrease acetylcholinesterase activity in a number of brain regions in patients with Alzheimer's disease. There is also a significant correlation between acetylcholinesterase inhibition and observed cognitive improvement. However, the cholinesterase inhibitors are reported to have additional pharmacological actions. Rivastigmine inhibits butyrylcholinesterase with a similar affinity to acetylcholinesterase, although it is not clear whether the inhibition of butyrylcholinesterase contributes to the therapeutic effect of rivastigmine. Based on data from preclinical studies, it has been proposed that galantamine also potentiates the action of acetylcholine on nicotinic receptors via allosteric modulation; however, the effects appear to be highly dependent on the concentrations of agonist and galantamine. It is not yet clear whether these concentrations are related to those achieved in the brain of patients with Alzheimer's disease within therapeutic dose ranges. Preclinical studies have shown that donepezil and galantamine also significantly increase nicotinic receptor density, and increased receptor density may be associated with enhanced synaptic strengthening through long-term potentiation, which is related to cognitive function. Despite these differences in pharmacology, a review of clinical data, including head-to-head studies, has not demonstrated differences in efficacy, although they may have an impact on tolerability. It seems clear that whatever the subsidiary modes of action, clinical evidence supporting acetylcholinesterase inhibition as the mechanism by which cholinesterase inhibitors treat the symptoms of Alzheimer's disease is accumulating. Certainly, as a class, the currently approved cholinesterase inhibitors (donepezil, galantamine, rivastigmine and tacrine) provide important benefits in patients with Alzheimer's disease and these drugs offer a significant advance in the management of dementia.
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Affiliation(s)
- David G Wilkinson
- Memory Assessment and Research Centre, Moorgreen Hospital, Southampton, UK.
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89
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Bohme GA, Letchworth SR, Piot-Grosjean O, Gatto GJ, Obinu MC, Caldwell WS, Laville M, Brunel P, Pellerin R, Leconte JP, Genevois-Borella A, Dubedat P, Mazadier M, Pradier L, Bencherif M, Benavides J. In vitro and in vivo characterization of TC-1827, a novel brain?4?2 nicotinic receptor agonist with pro-cognitive activity. Drug Dev Res 2004. [DOI: 10.1002/ddr.10352] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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90
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Hogg RC, Raggenbass M, Bertrand D. Nicotinic acetylcholine receptors: from structure to brain function. Rev Physiol Biochem Pharmacol 2003; 147:1-46. [PMID: 12783266 DOI: 10.1007/s10254-003-0005-1] [Citation(s) in RCA: 365] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
Nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels and can be divided into two groups: muscle receptors, which are found at the skeletal neuromuscular junction where they mediate neuromuscular transmission, and neuronal receptors, which are found throughout the peripheral and central nervous system where they are involved in fast synaptic transmission. nAChRs are pentameric structures that are made up of combinations of individual subunits. Twelve neuronal nAChR subunits have been described, alpha2-alpha10 and beta2-beta4; these are differentially expressed throughout the nervous system and combine to form nAChRs with a wide range of physiological and pharmacological profiles. The nAChR has been proposed as a model of an allosteric protein in which effects arising from the binding of a ligand to a site on the protein can lead to changes in another part of the molecule. A great deal is known about the structure of the pentameric receptor. The extracellular domain contains binding sites for numerous ligands, which alter receptor behavior through allosteric mechanisms. Functional studies have revealed that nAChRs contribute to the control of resting membrane potential, modulation of synaptic transmission and mediation of fast excitatory transmission. To date, ten genes have been identified in the human genome coding for the nAChRs. nAChRs have been demonstrated to be involved in cognitive processes such as learning and memory and control of movement in normal subjects. Recent data from knockout animals has extended the understanding of nAChR function. Dysfunction of nAChR has been linked to a number of human diseases such as schizophrenia, Alzheimer's and Parkinson's diseases. nAChRs also play a significant role in nicotine addiction, which is a major public health concern. A genetically transmissible epilepsy, ADNFLE, has been associated with specific mutations in the gene coding for the alpha4 or beta2 subunits, which leads to altered receptor properties.
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Affiliation(s)
- R C Hogg
- Department of Physiology, CMU, 1 rue Michel Servet, 1211 Geneva 4, Switzerland.
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91
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Abstract
Emerging therapies for Alzheimer's disease offer hope to patients and their caregivers. Future treatments will probably include combination approaches with agents that modify amyloid processing, deposition, and clearance. One example, the AD vaccine, reduced amyloid burden and changed behavior in animal models of AD, but the human trial was halted when several subjects developed brain inflammation. Anti-inflammatory agents have epidemiologic support, but clinical trials have been disappointing, possibly related to inadequate study with anti-inflammatory agents that modify amyloid processing. Agents that target known cardiovascular risk factors, such as hypercholesterolemia, hypertension, and insulin resistance, have epidemiologic, preclinical, and clinical evidence to warrant further investigation. Heavy metal chelators, antioxidants, neurotrophic factors, glutaminergic modulators, and agents that modify hyperphosphorylation of Tau are other approaches in research and development.
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Affiliation(s)
- Steven C Samuels
- Department of Psychiatry, Mount Sinai School of Medicine, New York, New York, USA.
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92
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Bachurin SO. Medicinal chemistry approaches for the treatment and prevention of Alzheimer's disease. Med Res Rev 2003; 23:48-88. [PMID: 12424753 DOI: 10.1002/med.10026] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Alzheimer's disease (AD) is the most common form of dementia, which is characterised by progressive deterioration of memory and higher cortical functions that ultimately result in total degradation of intellectual and mental activities. Modern strategies in the search of new therapeutic approaches are based on the morphological and biochemical characteristics of AD, and focused on following directions: agents that compensate the hypofunction of cholinergic system, agents that interfere with the metabolism of beta-amyloid peptide, agents that protect nerve cells from toxic metabolites formed in neurodegenerative processes, agents that activate other neurotransmitter systems that indirectly compensate for the deficit of cholinergic functions, agents that affect the process of the formation of neurofibrillary tangles, anti-inflammatory agents that prevent the negative response of nerve cells to the pathological process. The goal of the present review is the validation and an analysis from the point of view of medicinal chemistry of the principles of the directed search of drugs for the treatment and prevention of AD and related neurodegenerative disorders. It is based on systematization of the data on biochemical and structural similarities in the interaction between physiologically active compounds and their biological targets related to the development of such pathologies. The main emphasis is on cholinomimetic, anti-amyloid and anti-metabolic agents, using the data that were published during the last 3 to 4 years, as well as the results of clinical trials presented on corresponding websites.
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Affiliation(s)
- S O Bachurin
- Institute of Physiologically Active Compounds, Russian Academy of Sciences, 142432 Chernogolovka, Moscow region, Russia.
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93
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Abstract
Nicotinic receptors (NRs) belong to the group of polymeric receptors of the cell membrane and are key elements of cholinergic transmission. Numerous subtypes of NRs exist with the alpha 4 beta 2 and alpha 7 types being encountered most frequently. Deficiencies in NRs seem to play a role in Alzheimer's disease, which is characterised by accumulation of senile plaques, mainly composed of beta-amyloid peptide (beta A). Although the aetiology of this disease is unknown, different pathogenesis hypotheses implicating alpha 7 NRs have been proposed, with the receptors exerting a direct or indirect action on the mechanism of beta A toxicity. Allosteric modulators of NRs, such as the cholinesterase inhibitor galantamine, that facilitate the action of acetylcholine on these receptors may provide therapeutic benefits in the areas of cognition, attention and antineurodegenerative activity.
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Affiliation(s)
- Michel Bourin
- Research Group Neurobiology of Anxiety and Depression, Faculty of Medicine, Nantes, France.
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Luine VN, Mohan G, Tu Z, Efange SMN. Chromaproline and Chromaperidine, nicotine agonists, and Donepezil, cholinesterase inhibitor, enhance performance of memory tasks in ovariectomized rats. Pharmacol Biochem Behav 2002; 74:213-20. [PMID: 12376170 DOI: 10.1016/s0091-3057(02)00988-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Chromaproline and Chromaperidine, two recently synthesized and pharmacologically characterized nicotinic agonists, and Donepezil (Aricept), an acetylcholinesterase inhibitor approved for the treatment of memory loss, were evaluated for effects on performance of a visual recognition memory task (object recognition) and a spatial memory task (object placement). Ovariectomized female rats received the drugs chronically via subcutaneous Alzet minipumps. None of the drugs altered activity in the open field or the time spent exploring objects in the field. One week following initiation of treatment, all three drugs enhanced performance of the visual recognition task, but only Donepezil enhanced performance of the spatial memory task. With a longer period of treatment (3 weeks), the nicotinic agonist Chromaproline also enhanced object placement performance. Current results show the memory-enhancing efficacy of Donepezil in two additional memory tasks in rats and suggest that the novel nicotinic agonists, Chromaproline and Chromaperidine, may also be useful new drugs for the treatment of memory impairments/loss.
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Affiliation(s)
- V N Luine
- Department of Psychology, Hunter College of CUNY, 695 Park Avenue, New York, NY 10021, USA.
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95
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Auld DS, Kornecook TJ, Bastianetto S, Quirion R. Alzheimer's disease and the basal forebrain cholinergic system: relations to beta-amyloid peptides, cognition, and treatment strategies. Prog Neurobiol 2002; 68:209-45. [PMID: 12450488 DOI: 10.1016/s0301-0082(02)00079-5] [Citation(s) in RCA: 472] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Alzheimer's disease (AD) is the most common form of degenerative dementia and is characterized by progressive impairment in cognitive function during mid- to late-adult life. Brains from AD patients show several distinct neuropathological features, including extracellular beta-amyloid-containing plaques, intracellular neurofibrillary tangles composed of abnormally phosphorylated tau, and degeneration of cholinergic neurons of the basal forebrain. In this review, we will present evidence implicating involvement of the basal forebrain cholinergic system in AD pathogenesis and its accompanying cognitive deficits. We will initially discuss recent results indicating a link between cholinergic mechanisms and the pathogenic events that characterize AD, notably amyloid-beta peptides. Following this, animal models of dementia will be discussed in light of the relationship between basal forebrain cholinergic hypofunction and cognitive impairments in AD. Finally, past, present, and future treatment strategies aimed at alleviating the cognitive symptomatology of AD by improving basal forebrain cholinergic function will be addressed.
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Affiliation(s)
- Daniel S Auld
- Douglas Hospital Research Centre, 6875 Blvd Lasalle, Verdun, Que, Canada H4H 1R3
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Vesey R, Birrell JM, Bolton C, Chipperfield RS, Blackwell AD, Dening TR, Sahakian BJ. Cholinergic nicotinic systems in Alzheimer's disease: prospects for pharmacological intervention. CNS Drugs 2002; 16:485-500. [PMID: 12056923 DOI: 10.2165/00023210-200216070-00005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Within the last few years, research into the cause and progression of Alzheimer's disease has made significant advances. Although there is still no preventative treatment or cure for this neurodegenerative illness, the development of drugs that may alleviate some of the cognitive symptoms associated with it is advancing. Cholinesterase inhibitors are at present the most effective form of treatment and have shown significant overall response rates in clinical trials. However, although some patients show substantial improvement when treated with this class of drugs, there is considerable variability in the amount of benefit gained in different individuals in terms of their cognitive and behavioural functioning. Furthermore, unfortunately some patients gain little or no benefit from these drugs. It would therefore be of great advantage to explore alternative therapeutic possibilities. This article reviews the potential involvement of the nicotinic cholinergic system in Alzheimer's disease and discusses the possibility of nicotinic pharmacotherapy. Substantial evidence indicates the involvement of the nicotinic cholinergic system in the pathology of Alzheimer's disease. Drugs targeting these sites may not only have a positive effect on cognitive function, but also have additional therapeutic benefits in terms of restoring the hypoactivity in the excitatory amino acid pyramidal system and even slowing the emergence of Alzheimer's disease pathology. The conclusion of this review is that nicotinic treatments are an important potential source of new therapeutic interventions in Alzheimer's disease.
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Affiliation(s)
- Robyn Vesey
- Department of Psychiatry, University of Cambridge School of Clinical Medicine, Addenbrooke's Hospital, Cambridge, UK
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Engeland C, Mahoney C, Mohr E, Ilivitsky V, Knott VJ. Acute nicotine effects on auditory sensory memory in tacrine-treated and nontreated patients with Alzheimer's disease: an event-related potential study. Pharmacol Biochem Behav 2002; 72:457-64. [PMID: 11900820 DOI: 10.1016/s0091-3057(02)00711-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The auditory mismatch negativity (MMN) event-related brain potential (ERP) reflects the storage of information in acoustic sensory memory. Thirteen patients with Alzheimer's disease (AD), 6 receiving treatment with the cholinesterase inhibitor, tacrine [tetrahydroaminoacridine (THA)], and 7 receiving no treatment, were administered 2 mg of nicotine polacrilex and placebo. MMNs were recorded with 1- and 3-s interstimulus intervals (ISIs) during pre- and post-placebo/nicotine administration. Amplitudes decreased from pre- to post-placebo recordings in nontreated patients but remained stable in THA-treated patients. Comparison of pre- and post-nicotine MMNs found amplitude increases with nicotine in nontreated but not in THA-treated patients. MMN latencies were shortened by nicotine in both treatment groups. These exploratory findings suggest that nicotine-improved strength of acoustic sensory memory traces and speed of acoustic sensory discrimination in AD are differentially affected by chronic tacrine treatment.
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Affiliation(s)
- C Engeland
- Department of Psychiatry and Psychology, University of Western Ontario, London, ON, Canada
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Levin ED, Christopher NC. Persistence of nicotinic agonist RJR 2403-induced working memory improvement in rats. Drug Dev Res 2002. [DOI: 10.1002/ddr.10024] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Turégano L, Martínez-Rodríguez R, Alvarez MI, Gragera RR, Gómez de Segura A, De Miguel E, Toledano A. Histochemical study of acute and chronic intraperitoneal nicotine effects on several glycolytic and Krebs cycle dehydrogenase activities in the frontoparietal cortex and subcortical nuclei of the rat brain. J Neurosci Res 2001; 64:626-35. [PMID: 11398187 DOI: 10.1002/jnr.1116] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The effects of nicotine on the activity of different dehydrogenases in frontoparietal regions and subcortical nuclei of the rat brain have been studied using histochemical methods. Nicotine sulphate was intraperitoneally administered in acute (4 mg/kg/day x 3 days) or chronic (ALZET osmotic pump providing 2 mg/kg/day x 15 days) doses. The enzymes analyzed were glyceraldehyde-3-phosphate, lactate, malate and succinate dehydrogenases (gly3PDH, LDH, MDH, and SDH, respectively). The results demonstrate that chronic as well as acute administration of nicotine produced strong increases in all these enzymatic activities in the superior layers (I, II and III) of the frontoparietal cortex (cingulate, motor and somatosensory regions); but high increases were not seen in the deeper layers of the cortex or in the subcortical nuclei (substantia nigra, caudate-putamen, nucleus accumbens or nucleus basalis magnocellularis). These hyperactivities were produced in brain regions with normally low enzymatic activity (cortex), but not in those with great intensity (subcortical nuclei). The results are in rough agreement with previous reports on nicotine-induced increases in glucose utilization, gly3PDH genic expression and neuronal hyperactivity in the brain cortex; but significant discrepancies between the cortical enzymatic maps and those obtained both in these studies and others on nicotine(N)-receptor localization have been appreciated. The results support the hypothesis that nicotinic cholinergic drugs can have metabolic, long-lasting stimulant effects on cortical neurons at specific points (probably layer III pyramidal cells and structures with alpha7-N-receptors) of the cortical circuits that could be of great interest in improving altered cognitive functions that are present in Alzheimer disease, as well as in other less severe mental disturbances. Mitochondrial hyperfunction should also be evaluated as a possible side-effect (as an oxidative stress inductor) of these kinds of drugs.
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Affiliation(s)
- L Turégano
- Experimental Research Center, La Paz Hospital, INSALUD, Madrid, Spain
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Affiliation(s)
- P A Newhouse
- Clinical Neuroscience Research Unit, Department of Psychiatry, University of Vermont College of Medicine, Burlington, Vermont 05401-1195, USA
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