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Lane EL, Daly CS, Smith GA, Dunnett SB. Context-driven changes in L-DOPA-induced behaviours in the 6-OHDA lesioned rat. Neurobiol Dis 2011; 42:99-107. [PMID: 21220017 DOI: 10.1016/j.nbd.2011.01.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Revised: 12/07/2010] [Accepted: 01/02/2011] [Indexed: 10/18/2022] Open
Abstract
Both contralateral rotational behaviour and dyskinetic abnormal involuntary movements (AIMs) are induced by the administration of l-DOPA in the unilateral 6-OHDA lesioned rat model of Parkinson's disease. Since rotational responses can be conditioned to environmental cues we have investigated the extent to which drug-induced AIMS may also be conditioned by exteroceptive cues and experience. In Experiment I, 6-OHDA lesioned rats received repeated daily injections of l-DOPA either in their home cage (control) or in association with a brief (20 mins) exposure to the rotometers (paired). To assess conditioning, all animals then received two tests in the rotometer bowls. Following injection of saline the paired group both rotated more contralaterally and displayed manifest AIMs, neither of which were exhibited by the control rats. Moreover, following injection of l-DOPA, the paired group showed a trend for increased AIMs compared to controls. Two further studies provided longer exposure to the conditioning environments in counterbalanced designs. Although, using these parameters, re-exposure in the presence of saline did not induce context-dependent AIMs, a strong context-specific component of the sensitised response to l-DOPA was seen; chronic administration of drug produced a significantly stronger behavioural response in animals paired with a particular environment for drug administration than controls. This data suggests that part of the sensitisation of behavioural responding to l-DOPA administration is not solely a pharmacological phenomenon, but is also conditioned to the environmental context in which the drug is administered. This has clear implications for the clinical observation and experimental measurement of drug-induced dyskinesia in Parkinson's disease patients and animal models.
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Affiliation(s)
- E L Lane
- Brain Repair Group, School of Biosciences, Cardiff University, Cardiff, Wales, CF10 3AX, UK.
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102
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103
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Pisani V, Madeo G, Tassone A, Sciamanna G, Maccarrone M, Stanzione P, Pisani A. Homeostatic changes of the endocannabinoid system in Parkinson's disease. Mov Disord 2010; 26:216-22. [DOI: 10.1002/mds.23457] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2010] [Revised: 08/09/2010] [Accepted: 09/03/2010] [Indexed: 12/23/2022] Open
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104
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The effects of cannabinoid drugs on abnormal involuntary movements in dyskinetic and non-dyskinetic 6-hydroxydopamine lesioned rats. Brain Res 2010; 1363:40-8. [DOI: 10.1016/j.brainres.2010.09.086] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2010] [Revised: 09/22/2010] [Accepted: 09/24/2010] [Indexed: 11/22/2022]
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105
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Johnston TH, Huot P, Fox SH, Wakefield JD, Sykes KA, Bartolini WP, Milne GT, Pearson JP, Brotchie JM. Fatty Acid Amide Hydrolase (FAAH) Inhibition Reduces l-3,4-Dihydroxyphenylalanine-Induced Hyperactivity in the 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine-Lesioned Non-Human Primate Model of Parkinson's Disease. J Pharmacol Exp Ther 2010; 336:423-30. [DOI: 10.1124/jpet.110.169532] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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106
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Scotter EL, Abood ME, Glass M. The endocannabinoid system as a target for the treatment of neurodegenerative disease. Br J Pharmacol 2010; 160:480-98. [PMID: 20590559 DOI: 10.1111/j.1476-5381.2010.00735.x] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The Cannabis sativa plant has been exploited for medicinal, agricultural and spiritual purposes in diverse cultures over thousands of years. Cannabis has been used recreationally for its psychotropic properties, while effects such as stimulation of appetite, analgesia and anti-emesis have lead to the medicinal application of cannabis. Indeed, reports of medicinal efficacy of cannabis can been traced back as far as 2700 BC, and even at that time reports also suggested a neuroprotective effect of the cultivar. The discovery of the psychoactive component of cannabis resin, Delta(9)-tetrahydrocannabinol (Delta(9)-THC) occurred long before the serendipitous identification of a G-protein coupled receptor at which Delta(9)-THC is active in the brain. The subsequent finding of endogenous cannabinoid compounds, the synthesis of which is directed by neuronal excitability and which in turn served to regulate that excitability, further widened the range of potential drug targets through which the endocannabinoid system can be manipulated. As a result of this, alterations in the endocannabinoid system have been extensively investigated in a range of neurodegenerative disorders. In this review we examine the evidence implicating the endocannabinoid system in the cause, symptomatology or treatment of neurodegenerative disease. We examine data from human patients and compare and contrast this with evidence from animal models of these diseases. On the basis of this evidence we discuss the likely efficacy of endocannabinoid-based therapies in each disease context.
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Affiliation(s)
- Emma L Scotter
- Centre for Brain Research and Department of Pharmacology, University of Auckland, Auckland, New Zealand
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107
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Tadaiesky MT, Dombrowski PA, Da Cunha C, Takahashi RN. Effects of SR141716A on Cognitive and Depression-Related Behavior in an Animal Model of Premotor Parkinson's Disease. PARKINSONS DISEASE 2010; 2010:238491. [PMID: 20976080 PMCID: PMC2957172 DOI: 10.4061/2010/238491] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Revised: 07/16/2010] [Accepted: 08/31/2010] [Indexed: 11/20/2022]
Abstract
A previous study from our laboratory revealed that moderate nigral dopaminergic degeneration caused emotional and cognitive deficits in rats, paralleling early signs of Parkinson's disease. Recent evidence suggests that the blockade of cannabinoid CB1 receptors might be beneficial to alleviate motor inhibition typical of Parkinson's disease. Here, we investigated whether antagonism of CB1 receptors would improve emotional and cognitive deficits in a rat model of premotor Parkinson's disease. Depression-like behavior and cognition were assessed with the forced swim test and the social recognition test, respectively. Confirming our previous study, rats injected with 6-hydroxydopamine in striatum presented emotional and cognitive alterations which were improved by acute injection of SR141716A. HPLC analysis of monoamine levels demonstrated alterations in the striatum and prefrontal cortex after SR141716A injection. These findings suggest a role for CB1 receptors in the early symptoms caused by degeneration of dopaminergic neurons in the striatum, as observed in Parkinson's disease.
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Affiliation(s)
- M T Tadaiesky
- Departamento de Farmacologia, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina (UFSC), Campus Universitário, Trindade, Bloco D/CCB, P.O. Box 476, 88040-970 Florianópolis, SC, Brazil
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108
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Pisani V, Moschella V, Bari M, Fezza F, Galati S, Bernardi G, Stanzione P, Pisani A, Maccarrone M. Dynamic changes of anandamide in the cerebrospinal fluid of Parkinson's disease patients. Mov Disord 2010; 25:920-4. [PMID: 20461809 DOI: 10.1002/mds.23014] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
A correct balance between endocannabinoid and dopamine-dependent systems is believed to underlie physiological motor control. We measured the levels of the endocannabinoid anandamide in the cerebrospinal fluid of Parkinson's disease (PD) patients. Subjects were divided into three groups: newly diagnosed de novo patients, subjects undergoing drug withdrawal, and patients under pharmacological therapy. These groups were compared to age-matched control subjects. Anandamide levels in untreated patients were more than doubled as compared to controls. However, chronic dopaminergic replacement restored control anandamide levels. Abnormal anandamide increase might reflect a compensatory mechanism occurring in course of PD, aimed at normalizing dopamine depletion.
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Affiliation(s)
- Valerio Pisani
- Department of Neuroscience, University of Rome Tor Vergata, Rome, Italy
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109
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Abstract
Huntington's disease (HD) is caused by a CAG repeat expansion in exon 1 of the HD gene resulting in a long polyglutamine tract in the N-terminus of the protein huntingtin. Patients carrying the mutation display chorea in early stages followed by akinesia and sometimes dystonia in late stages. Other major symptoms include depression, anxiety, irritability or aggressive behavior, and apathy. Although many neuronal systems are affected, dysfunction and subsequent neurodegeneration in the basal ganglia and cortex are the most apparent pathologies. In HD, the primary hypothesis has been that there is an initial overactivity of glutamate neurotransmission that produces excitotoxicity followed by a series of complex changes that are different in the striatum and in the cortex. This review will focus on evidence for alterations in dopamine (DA)-glutamate interactions in HD, concentrating on the striatum and cortex. The most recent evidence points to decreases in DA and glutamate neurotransmission as the HD phenotype develops. However, there is some evidence for increased DA and glutamate functions that could be responsible for some of the early HD phenotype. Significant evidence indicates that glutamate and dopamine neurotransmission is affected in HD, compromising the fine balance in which DA modulates glutamate-induced excitation in the basal ganglia and cortex. Restoring the balance between glutamate and dopamine could be helpful to treat HD symptoms.
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110
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Abstract
There is now a large volume of data indicating that compounds activating cannabinoid CB(1) receptors, either directly or indirectly by preventing the breakdown of endogenous cannabinoids, can protect against neuronal damage produced by a variety of neuronal "insults". Given that such neurodegenerative stimuli result in increased endocannabinoid levels and that animals with genetic deletions of CB(1) receptors are more susceptible to the deleterious effects of such stimuli, a case can be made for an endogenous neuroprotective role of endocannabinoids. However, this is an oversimplification of the current literature, since (a) compounds released together with the endocannabinoids can contribute to the neuroprotective effect; (b) other proteins, such as TASK-1 and PPARalpha, are involved; (c) the CB(1) receptor antagonist/inverse agonist rimonabant has also been reported to have neuroprotective properties in a number of animal models of neurodegenerative disorders. Furthermore, the CB(2) receptor located on peripheral immune cells and activated microglia are potential targets for novel therapies. In terms of the clinical usefulness of targeting the endocannabinoid system for the treatment of neurodegenerative disorders, data are emerging, but important factors to be considered are windows of opportunity (for acute situations such as trauma and ischemia) and the functionality of the target receptors (for chronic neurodegenerative disorders such as Alzheimer's disease).
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111
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Fox SH, Brotchie JM. The MPTP-lesioned non-human primate models of Parkinson’s disease. Past, present, and future. PROGRESS IN BRAIN RESEARCH 2010; 184:133-57. [DOI: 10.1016/s0079-6123(10)84007-5] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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112
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Przybyla JA, Watts VJ. Ligand-induced regulation and localization of cannabinoid CB1 and dopamine D2L receptor heterodimers. J Pharmacol Exp Ther 2009; 332:710-9. [PMID: 20016021 DOI: 10.1124/jpet.109.162701] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The cannabinoid CB(1) (CB(1)) and dopamine D(2) (D(2)) receptors are coexpressed in the basal ganglia, an area of the brain involved in such processes as cognition, motor function, and emotional control. Several lines of evidence suggest that CB(1) and D(2) receptors may oligomerize, providing a unique pharmacology in vitro and in vivo. However, limited information exists on the regulation of CB(1) and D(2) receptor dimers. We used a novel technique, multicolor bimolecular fluorescence complementation (MBiFC) to examine the subcellular localization of CB(1)-D(2L) heterodimers as well as D(2L)-D(2L) homodimers in a neuronal cell model, Cath. a differentiated cells. MBiFC was then used to explore the effects of persistent ligand treatment on receptor dimerization at the plasma membrane and intracellularly. Persistent (20-h) agonist treatment resulted in increased formation of CB(1)-D(2L) heterodimers relative to the D(2L)-D(2L) homodimers. The effects of the D(2) agonist quinpirole were restricted to the intracellular compartment and may reflect increased D(2L) receptor expression. In contrast, treatment with the CB(1) receptor agonist (2)-cis-3-[2-hydroxy-4-(1,1-dimethylheptyl)phenyl]-trans-4-(3-hydroxypropyl) cyclohexanol (CP55, 940) produced increases in both membrane and intracellular CB(1)-D(2L) heterodimers independently of alterations in CB(1) receptor expression. The effects of CB(1) receptor activation were attenuated by the CB(1) antagonist 1-(2,4-dichlorophenyl)-5-(4-iodophenyl)-4-methyl-N-4-morpholinyl-1H-pyrazole-3-carboxamide (AM281) and were both time- and dose-dependent. The effects of CB(1) activation were examined further by combining MBiFC with a constitutively active CB(1) receptor mutant, CB(1)T210I. These studies demonstrated that the expression of CB(1)T210I increased intracellular CB(1)-D(2L) heterodimer formation. In summary, agonist-induced modulation of CB(1)-D(2L) oligomerization may have physiological implications in diseases such as Parkinson's disease and drug abuse.
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Affiliation(s)
- Julie A Przybyla
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, 575 Stadium Mall Dr., RHPH 210, West Lafayette, IN 47907-2091, USA
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113
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Basavarajappa BS, Nixon RA, Arancio O. Endocannabinoid system: emerging role from neurodevelopment to neurodegeneration. Mini Rev Med Chem 2009; 9:448-62. [PMID: 19356123 DOI: 10.2174/138955709787847921] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The endocannabinoid system, including endogenous ligands ('endocannabinoids' ECs), their receptors, synthesizing and degrading enzymes, as well as transporter molecules, has been detected from the earliest stages of embryonic development and throughout pre- and postnatal development. ECs are bioactive lipids, which comprise amides, esters and ethers of long chain polyunsaturated fatty acids. Anandamide (N-arachidonoylethanolamine; AEA) and 2-arachidonoylglycerol (2-AG) are the best studied ECs, and act as agonists of cannabinoid receptors. Thus, AEA and 2-AG mimic several pharmacological effects of the exogenous cannabinoid delta9-tetrahydrocannabinol (Delta(9)-THC), the psychoactive principle of cannabis sativa preparations like hashish and marijuana. Recently, however, several lines of evidence have suggested that the EC system may play an important role in early neuronal development as well as a widespread role in neurodegeneration disorders. Many of the effects of cannabinoids and ECs are mediated by two G protein-coupled receptors (GPCRs), CB1 and CB2, although additional receptors may be implicated. Both CB1 and CB2 couple primarily to inhibitory G proteins and are subject to the same pharmacological influences as other GPCRs. This new system is briefly presented in this review, in order to put in a better perspective the role of the EC pathway from neurodevelopment to neurodegenerative disorders, like Alzheimer's disease, Parkinson's disease, Huntington's disease, and multiple sclerosis. In addition, the potential exploitation of antagonists of CB1 receptors, or of inhibitors of EC metabolism, as next-generation therapeutics is discussed.
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Affiliation(s)
- Balapal S Basavarajappa
- Center for Dementia Research, Nathan Kline Institute for Psychiatric Research, 140 Old Orangeburg Rd, Orangeburg, NY 10962, USA.
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114
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Giuffrida A, McMahon LR. In vivo pharmacology of endocannabinoids and their metabolic inhibitors: therapeutic implications in Parkinson's disease and abuse liability. Prostaglandins Other Lipid Mediat 2009; 91:90-103. [PMID: 19523530 DOI: 10.1016/j.prostaglandins.2009.05.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2009] [Revised: 05/19/2009] [Accepted: 05/26/2009] [Indexed: 01/03/2023]
Abstract
This review focuses on the behavioral pharmacology of endogenous cannabinoids (endocannabinoids) and indirect-acting cannabinoid agonists that elevate endocannabinoid tone by inhibiting the activity of metabolic enzymes. Similarities and differences between prototype cannabinoid agonists, endocannabinoids and inhibitors of endocannabinoid metabolism are discussed in the context of endocannabinoid pharmacokinetics in vivo. The distribution and function of cannabinoid and non-CB(1)/CB(2) receptors are also covered, with emphasis on their role in disorders characterized by dopamine dysfunction, such as drug abuse and Parkinson's disease. Finally, evidence is presented to suggest that FAAH inhibitors lack the abuse liability associated with CB(1) agonists, although they may modify the addictive properties of other drugs, such as alcohol.
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Affiliation(s)
- Andrea Giuffrida
- Department of Pharmacology, University of Texas Health Science Center, San Antonio, TX 78229, USA.
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115
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Ligresti A, Petrosino S, Di Marzo V. From endocannabinoid profiling to ‘endocannabinoid therapeutics’. Curr Opin Chem Biol 2009; 13:321-31. [DOI: 10.1016/j.cbpa.2009.04.615] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2009] [Accepted: 04/17/2009] [Indexed: 12/31/2022]
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116
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Price DA, Martinez AA, Seillier A, Koek W, Acosta Y, Fernandez E, Strong R, Lutz B, Marsicano G, Roberts JL, Giuffrida A. WIN55,212-2, a cannabinoid receptor agonist, protects against nigrostriatal cell loss in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine mouse model of Parkinson's disease. Eur J Neurosci 2009; 29:2177-86. [PMID: 19490092 DOI: 10.1111/j.1460-9568.2009.06764.x] [Citation(s) in RCA: 174] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Parkinson's disease (PD) is characterized by the progressive loss of nigrostriatal dopamine neurons leading to motor disturbances and cognitive impairment. Current pharmacotherapies relieve PD symptoms temporarily but fail to prevent or slow down the disease progression. In this study, we investigated the molecular mechanisms by which the non-selective cannabinoid receptor agonist WIN55,212-2 (WIN) protects mouse nigrostriatal neurons from 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced neurotoxicity and neuroinflammation. Stereological analyses showed that chronic treatment with WIN (4 mg/kg, intraperitoneal), initiated 24 h after MPTP administration, protected against MPTP-induced loss of tyrosine hydroxylase-positive neurons in the substantia nigra pars compacta independently of CB1 cannabinoid receptor activation. The neuroprotective effect of WIN was accompanied by increased dopamine and 3,4-dihydroxyphenylacetic acid levels in the substantia nigra pars compacta and dorsal striatum of MPTP-treated mice. At 3 days post-MPTP, we found significant microglial activation and up-regulation of CB2 cannabinoid receptors in the ventral midbrain. Treatment with WIN or the CB2 receptor agonist JWH015 (4 mg/kg, intraperitoneal) reduced MPTP-induced microglial activation, whereas genetic ablation of CB2 receptors exacerbated MPTP systemic toxicity. Furthermore, chronic WIN reversed MPTP-associated motor deficits, as revealed by the analysis of forepaw step width and percentage of faults using the inverted grid test. In conclusion, our data indicate that agonism at CB2 cannabinoid receptors protects against MPTP-induced nigrostriatal degeneration by inhibiting microglial activation/infiltration and suggest that CB2 receptors represent a new therapeutic target to slow the degenerative process occurring in PD.
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Affiliation(s)
- David A Price
- Department of Pharmacology, University of Texas Health Science Center, San Antonio, TX, USA
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117
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Pérez-Rial S, García-Gutiérrez MS, Molina JA, Pérez-Nievas BG, Ledent C, Leiva C, Leza JC, Manzanares J. Increased vulnerability to 6-hydroxydopamine lesion and reduced development of dyskinesias in mice lacking CB1 cannabinoid receptors. Neurobiol Aging 2009; 32:631-45. [PMID: 19419794 DOI: 10.1016/j.neurobiolaging.2009.03.017] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2008] [Revised: 03/10/2009] [Accepted: 03/27/2009] [Indexed: 01/04/2023]
Abstract
Motor impairment, dopamine (DA) neuronal activity and proenkephalin (PENK) gene expression in the caudate-putamen (CPu) were measured in 6-OHDA-lesioned and treated (L-DOPA+benserazide) CB1 KO and WT mice. A lesion induced by 6-OHDA produced more severe motor deterioration in CB1 KO mice accompanied by more loss of DA neurons and increased PENK gene expression in the CPu. Oxidative/nitrosative and neuroinflammatory parameters were estimated in the CPu and cingulate cortex (Cg). CB1 KO mice exhibited higher MDA levels and iNOS protein expression in the CPu and Cg compared to WT mice. Treatment with L-DOPA+benserazide (12 weeks) resulted in less severe dyskinesias in CB1 KO than in WT mice. The results revealed that the lack of cannabinoid CB1 receptors increased the severity of motor impairment and DA lesion, and reduced L-DOPA-induced dyskinesias. These results suggest that activation of CB1 receptors offers neuroprotection against dopaminergic lesion and the development of L-DOPA-induced dyskinesias.
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Affiliation(s)
- Sandra Pérez-Rial
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, Apartado de correos 18, 03550 San Juan de Alicante, Spain
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118
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Kelsey JE, Harris O, Cassin J. The CB(1) antagonist rimonabant is adjunctively therapeutic as well as monotherapeutic in an animal model of Parkinson's disease. Behav Brain Res 2009; 203:304-7. [PMID: 19414037 DOI: 10.1016/j.bbr.2009.04.035] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2009] [Revised: 04/22/2009] [Accepted: 04/27/2009] [Indexed: 11/16/2022]
Abstract
Acute injections of 8mg/kg of 3,4-dihydroxy-l-phenylalanine (l-DOPA) or 0.05mg/kg rimonabant equally improved contralateral forepaw stepping in rats with unilateral 6-hydroxydopamine (6-OHDA) lesions, and their combination improved stepping more than either drug alone. However, 0.05mg/kg rimonabant did not alter the changes in stepping produced by acute injections of a dyskinesic dose of 35mg/kg l-DOPA. Thus, not only is a cannabinoid antagonist monotherapeutic in this animal model of Parkinson's disease, but it also enhances the therapeutic effect of a moderate, but not a high, dose of l-DOPA.
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Affiliation(s)
- J E Kelsey
- Program in Neuroscience, Bates College, Lewiston, ME 04240, United States.
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119
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Fernández-Ruiz J. The endocannabinoid system as a target for the treatment of motor dysfunction. Br J Pharmacol 2009; 156:1029-40. [PMID: 19220290 DOI: 10.1111/j.1476-5381.2008.00088.x] [Citation(s) in RCA: 126] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
There is evidence that cannabinoid-based medicines that are selective for different targets in the cannabinoid signalling system (e.g. receptors, inactivation mechanism, enzymes) might be beneficial in basal ganglia disorders, namely Parkinson's disease (PD) and Huntington's disease (HD). These benefits not only include the alleviation of specific motor symptoms [e.g. choreic movements with cannabinoid receptor type 1 (CB(1))/transient receptor potential vanilloid type 1 agonists in HD; bradykinesia with CB(1) antagonists and tremor with CB(1) agonists in PD], but also the delay of disease progression due to the neuroprotective properties demonstrated for cannabinoids (e.g. CB(1) agonists reduce excitotoxicity; CB(2) agonists limit the toxicity of reactive microglia; and antioxidant cannabinoids attenuate oxidative damage). In addition, extensive biochemical, anatomical, physiological and pharmacological studies have demonstrated that: (i) the different elements of the cannabinoid system are abundant in basal ganglia structures and they are affected by these disorders; (ii) the cannabinoid system plays a prominent role in basal ganglia function by modulating the neurotransmitters that operate in the basal ganglia circuits, both in healthy and pathological conditions; and (iii) the activation and/or inhibition of the cannabinoid system is associated with important motor responses that are maintained and even enhanced in conditions of malfunctioning and/or degeneration. In this article we will review the available data regarding the relationship between the cannabinoid system and basal ganglia activity, both in healthy and pathological conditions and will also try to identify future lines of research expected to increase current knowledge about the potential therapeutic benefits of targeting this system in PD, HD and other basal ganglia disorders.
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Affiliation(s)
- Javier Fernández-Ruiz
- Departamento de Bioquímica y Biología Molecular and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Facultad de Medicina, Universidad Complutense, Madrid, Spain
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120
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Fornai F, Biagioni F, Fulceri F, Murri L, Ruggieri S, Paparelli A. Intermittent Dopaminergic stimulation causes behavioral sensitization in the addicted brain and parkinsonism. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2009; 88:371-98. [PMID: 19897084 DOI: 10.1016/s0074-7742(09)88013-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The gold standard therapy for Parkinson's disease (PD) consists in chronic administration of pulses of the dopamine (DA) precursor l-dihydroxyphenylalanine (l-DOPA). Although the main brain area which is DA-deficient is the dorsal striatum (more the putamen than the caudate nucleus), other DA-innervated brain regions (i.e., the ventral striatum and other limbic areas) are affected by systemic administration of l-DOPA. While such a therapy produces an increase in synaptic and nonsynaptic DA, which replace the neurotransmitter deficiency, peaks of extracellular DA in the course of disease progression produce abnormal involuntary movements related to behavioral sensitization. Methamphetamine (METH), a widely abused drug, is known to produce behavioral sensitization, related to DA release (more in the ventral than dorsal striatum as well as other limbic regions). The present review discusses the overlapping between these treatments, based on pulses of DA stimulation with an emphasis on the class of DA receptors; signal transduction pathways; rearranged expression of neurotransmitters, cotransmitters, and their receptors coupled with ultrastructural changes. In fact, all these levels of synaptic plasticity show a surprising homology following these treatments, posing the mechanisms of behavioral sensitization during DA-replacement therapy in PD very close to the neurobiological mechanisms operating during METH abuse. In line with this view is the growing evidence of addictive behaviors in PD patients during the course of DA-replacement therapy.
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Affiliation(s)
- Francesco Fornai
- Department of Human Morphology and Applied Biology, University of Pisa, Pisa, Italy
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121
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Visanji NP, Fox SH, Johnston TH, Millan MJ, Brotchie JM. Alpha1-adrenoceptors mediate dihydroxyphenylalanine-induced activity in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-lesioned macaques. J Pharmacol Exp Ther 2008; 328:276-83. [PMID: 18955589 DOI: 10.1124/jpet.108.144097] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The mechanisms underlying actions of dihydroxyphenylalanine (L-DOPA) in Parkinson's disease remain to be fully elucidated. Noradrenaline formed from L-DOPA may stimulate alpha(1)-adrenoceptors. We assessed the involvement of alpha(1)-adrenoceptors in actions of L-DOPA in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-lesioned macaques. In each animal, the minimal dose of L-DOPA required to alleviate parkinsonian symptoms was defined (12.5-25 mg/kg p.o.). The effects of coadministration of the alpha(1)-adrenoceptor antagonist prazosin ([4-(4-amino-6,7-dimethoxy-quinazolin-2-yl) piperazin-1-yl]-(2-furyl)methanone) on motor activity, parkinsonism, and dyskinesia were assessed. Antiparkinsonian benefit was accompanied by mild dyskinesia. L-DOPA also elicited hyperactivity, i.e., activity greater than that seen in normal animals. Coadministration of prazosin (0.16-0.63 mg/kg p.o.) with L-DOPA did not significantly affect either its antiparkinsonian actions or dyskinesia. However, prazosin significantly and dose-dependently attenuated L-DOPA-induced activity, reducing it to a level equivalent to that of normal animals. More specifically, during periods of pronounced L-DOPA-induced activity, prazosin attenuated the total and duration of activity by 80 and 76%, respectively. These actions of prazosin were expressed in the absence of sedation. Although activation of alpha(1)-adrenoceptors plays no major role in the antiparkinsonian and dyskinetic effects of L-DOPA per se, it does contribute to the induction of hyperactivity. alpha(1)-Adrenoceptors may be involved in pathological responses to L-DOPA treatment, including the dopamine dysregulation syndrome.
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Affiliation(s)
- N P Visanji
- Division of Brain Imaging and Behavior, Toronto Western Research Institute, 399 Bathurst St., Toronto, ON, Canada.
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122
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Calabresi P, Di Filippo M, Ghiglieri V, Picconi B. Molecular mechanisms underlying levodopa-induced dyskinesia. Mov Disord 2008; 23 Suppl 3:S570-9. [DOI: 10.1002/mds.22019] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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123
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Jenner P. Preventing and controlling dyskinesia in Parkinson's disease-A view of current knowledge and future opportunities. Mov Disord 2008; 23 Suppl 3:S585-98. [DOI: 10.1002/mds.22022] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
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124
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Di Marzo V. Targeting the endocannabinoid system: to enhance or reduce? Nat Rev Drug Discov 2008; 7:438-55. [PMID: 18446159 DOI: 10.1038/nrd2553] [Citation(s) in RCA: 618] [Impact Index Per Article: 38.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
As our understanding of the endocannabinoids improves, so does the awareness of their complexity. During pathological states, the levels of these mediators in tissues change, and their effects vary from those of protective endogenous compounds to those of dysregulated signals. These observations led to the discovery of compounds that either prolong the lifespan of endocannabinoids or tone down their action for the potential future treatment of pain, affective and neurodegenerative disorders, gastrointestinal inflammation, obesity and metabolic dysfunctions, cardiovascular conditions and liver diseases. When moving to the clinic, however, the pleiotropic nature of endocannabinoid functions will require careful judgement in the choice of patients and stage of the disorder for treatment.
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Affiliation(s)
- Vincenzo Di Marzo
- Endocannabinoid Research Group, Institute of Biomolecular Chemistry, National Research Council (CNR), Via Campi Flegrei 34, 80078, Pozzuoli, Naples, Italy.
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125
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Di Marzo V, Maccarrone M. FAAH and anandamide: is 2-AG really the odd one out? Trends Pharmacol Sci 2008; 29:229-33. [DOI: 10.1016/j.tips.2008.03.001] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2008] [Revised: 03/07/2008] [Accepted: 03/07/2008] [Indexed: 10/22/2022]
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126
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van Vliet SAM, Vanwersch RAP, Jongsma MJ, Olivier B, Philippens IHCHM. Therapeutic effects of Delta9-THC and modafinil in a marmoset Parkinson model. Eur Neuropsychopharmacol 2008; 18:383-9. [PMID: 18222654 DOI: 10.1016/j.euroneuro.2007.11.003] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2007] [Revised: 08/29/2007] [Accepted: 11/21/2007] [Indexed: 11/26/2022]
Abstract
Current therapies for Parkinson's disease (PD) like l-dopa and dopamine (DA) agonists have declined efficacy after long term use. Therefore, research towards supplementary or alternative medication is needed. The implementation in PD can be expedited by application of compounds already used in the clinic. In this study the therapeutic effects of the psychoactive compounds Delta(9)-tetrahydrocannabinol (Delta(9)-THC) and modafinil were tested in the 1-methyl-1,2,3,6-tetrahydropyridine (MPTP)-marmoset model for PD. The anti-parkinson effects of Delta(9)-THC (4 mg/kg) and modafinil (100 mg/kg) in parkinsonian marmosets were assessed with two behavioral rating scales covering parkinsonian symptoms and involuntary movements and two test systems assessing the locomotor activity and hand-eye coordination. Delta(9)-THC improved activity and hand-eye coordination, but induced compound-related side-effects. Modafinil improved activity and observed parkinsonian symptoms but not hand-eye coordination. It can be concluded that both compounds have therapeutic values and could supplement existing therapies for PD.
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Affiliation(s)
- Sanneke A M van Vliet
- Department of Diagnosis and Therapy, TNO Defence, Security and Safety, Rijswijk, The Netherlands.
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127
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Papa SM. The cannabinoid system in Parkinson's disease: multiple targets to motor effects. Exp Neurol 2008; 211:334-8. [PMID: 18433745 DOI: 10.1016/j.expneurol.2008.03.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2007] [Revised: 02/25/2008] [Accepted: 03/07/2008] [Indexed: 01/09/2023]
Affiliation(s)
- Stella M Papa
- Department of Neurology, Emory University School of Medicine, 6000 WMRC, 101 Woodruff Circle, Atlanta, Georgia, 30322, USA.
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128
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Morgese MG, Cassano T, Cuomo V, Giuffrida A. Anti-dyskinetic effects of cannabinoids in a rat model of Parkinson's disease: role of CB(1) and TRPV1 receptors. Exp Neurol 2007; 208:110-9. [PMID: 17900568 PMCID: PMC2128772 DOI: 10.1016/j.expneurol.2007.07.021] [Citation(s) in RCA: 142] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2007] [Revised: 07/23/2007] [Accepted: 07/30/2007] [Indexed: 11/17/2022]
Abstract
Levodopa is the most commonly prescribed drug for Parkinson's disease (PD). Although levodopa improves PD symptoms in the initial stages of the disease, its long-term use is limited by the development of side effects, including abnormal involuntary movements (dyskinesias) and psychiatric complications. The endocannabinoid system is emerging as an important modulator of basal ganglia functions and its pharmacologic manipulation represents a promising therapy to alleviate levodopa-induced dyskinesias. Rats with 6-OHDA lesions that are chronically treated with levodopa develop increasingly severe axial, limb, locomotor and oro-facial abnormal involuntary movements (AIMs). Administration of the cannabinoid agonist WIN 55,212-2 attenuated levodopa-induced axial, limb and oral AIMs dose-dependently via a CB(1)-mediated mechanism, whereas it had no effect on locomotive AIMs. By contrast, systemic administration of URB597, a potent FAAH inhibitor, did not affect AIMs scoring despite its ability to increase anandamide concentration throughout the basal ganglia. Unlike WIN, anandamide can also bind and activate transient receptor potential vanilloid type-1 (TRPV1) receptors, which have been implicated in the modulation of dopamine transmission in the basal ganglia. Interestingly, URB597 significantly decreased all AIMs subtypes only if co-administered with the TRPV1 antagonist capsazepine. Our data indicate that pharmacological blockade of TRPV1 receptors unmasks the anti-dyskinetic effects of FAAH inhibitors and that CB(1) and TRPV1 receptors play opposite roles in levodopa-induced dyskinesias.
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MESH Headings
- Amidohydrolases/antagonists & inhibitors
- Animals
- Antiparkinson Agents/adverse effects
- Antiparkinson Agents/pharmacology
- Arachidonic Acids/metabolism
- Basal Ganglia/metabolism
- Benzamides/therapeutic use
- Benzoxazines/therapeutic use
- Cannabinoids/agonists
- Capsaicin/analogs & derivatives
- Capsaicin/therapeutic use
- Carbamates/therapeutic use
- Drug Therapy, Combination
- Dyskinesia, Drug-Induced/metabolism
- Dyskinesia, Drug-Induced/physiopathology
- Endocannabinoids
- Levodopa/adverse effects
- Levodopa/therapeutic use
- Male
- Morpholines/therapeutic use
- Naphthalenes/therapeutic use
- Oxidopamine
- Parkinson Disease, Secondary/chemically induced
- Parkinson Disease, Secondary/drug therapy
- Polyunsaturated Alkamides/metabolism
- Rats
- Rats, Wistar
- Receptor, Cannabinoid, CB1/drug effects
- Receptor, Cannabinoid, CB1/metabolism
- TRPV Cation Channels/antagonists & inhibitors
- TRPV Cation Channels/metabolism
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Affiliation(s)
- Maria Grazia Morgese
- Department of Biomedical Sciences, University of Foggia, Viale Luigi Pinto 1, 71100 Foggia, Italy
- Department of Pharmacology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, Texas 78229
| | - Tommaso Cassano
- Department of Biomedical Sciences, University of Foggia, Viale Luigi Pinto 1, 71100 Foggia, Italy
| | - Vincenzo Cuomo
- Department of Human Physiology and Pharmacology, University of Rome “La Sapienza”, Piazzale Aldo Moro 5, 00185 Roma, Italy
| | - Andrea Giuffrida
- Department of Pharmacology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, Texas 78229
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129
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Galvan A, Wichmann T. GABAergic circuits in the basal ganglia and movement disorders. PROGRESS IN BRAIN RESEARCH 2007; 160:287-312. [PMID: 17499121 DOI: 10.1016/s0079-6123(06)60017-4] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
GABA is the major inhibitory neurotransmitter in the basal ganglia, and GABAergic pathways dominate information processing in most areas of these structures. It is therefore not surprising that abnormalities of GABAergic transmission are key elements in pathophysiologic models of movement disorders involving the basal ganglia. These include hypokinetic diseases such as Parkinson's disease, and hyperkinetic diseases, such as Huntington's disease or hemiballism. In this chapter, we will briefly review the major anatomic features of the GABAergic pathways in the basal ganglia, and then describe in greater detail the changes of GABAergic transmission, which are known to occur in movement disorders.
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Affiliation(s)
- Adriana Galvan
- Department of Neurology, School of Medicine and Yerkes National Primate Research Center, Emory University, Atlanta, GA 30322, USA.
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130
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Bisogno T, Di Marzo V. Short- and long-term plasticity of the endocannabinoid system in neuropsychiatric and neurological disorders. Pharmacol Res 2007; 56:428-42. [PMID: 17933549 DOI: 10.1016/j.phrs.2007.09.002] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2007] [Accepted: 09/05/2007] [Indexed: 12/30/2022]
Abstract
The activity of the endocannabinoid system, in terms of the levels of the endocannabinoids and of cannabinoid receptors, or of the functional coupling of the latter to a biological response, undergoes to remodelling during pathological conditions. In the CNS, these changes, depending also on the nature of the disorder, can be transient or long-lasting, occur only in those tissues involved in the pathological condition and usually aim at restoring the physiological homeostasis by reducing excitotoxicity, inflammation and neuronal death. However, during chronic disorders, prolonged activation of the endocannabinoid system might also contribute to the symptoms of the pathology. Whilst acute changes of the tissue levels of the endocannabinoids reflect the "on demand" nature of their biosynthesis and release, and hence are effected mostly through regulation of the biosynthetic enzymes, chronic changes seem to be mostly due to longer-lasting alterations in the expression of anabolic and catabolic enzymes. The possibility of obtaining therapeutic advantage from endocannabinoid plasticity in neuropsychiatric and neurological disorders is discussed in this review article.
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Affiliation(s)
- Tiziana Bisogno
- Endocannabinoid Research Group, Institute of Biomolecular Chemistry, Consiglio Nazionale delle Ricerche, Via Campi Flegrei 34, Pozzuoli, Naples, Italy
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131
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Cao X, Liang L, Hadcock JR, Iredale PA, Griffith DA, Menniti FS, Factor S, Greenamyre JT, Papa SM. Blockade of cannabinoid type 1 receptors augments the antiparkinsonian action of levodopa without affecting dyskinesias in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated rhesus monkeys. J Pharmacol Exp Ther 2007; 323:318-26. [PMID: 17630359 DOI: 10.1124/jpet.107.125666] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Drugs acting at cannabinoid type 1 receptors (CB1) have modulatory effects on glutamate and GABA neurotransmission in basal ganglia; thus, they potentially affect motor behavior in the parkinsonian setting. Preclinical trials with diverse cannabinoid agents have shown varied results, and the precise effects of blocking cannabinoid CB1 receptors remain uncertain. We tested behavioral effects of the selective antagonist 1-[7-(2-chlorophenyl)-8-(4-chlorophenyl)-2-methylpyrazolo[1,5-a]-[1,3,5]triazin-4-yl]-3-ethylaminoazetidine-3-carboxylic acid amide benzenesulfonate (CE) as monotherapy and in combination with l-DOPA in treatment-naive and L-DOPA-primed 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated rhesus monkeys with moderate and severe parkinsonism. Motor disability and L-DOPA-induced dyskinesias were scored with a standardized scale after subcutaneous drug administration, and plasma levels of L-DOPA were determined by high-performance liquid chromatography/electrochemical detection. CE doses ranged from 0.03 to 1 mg/kg, and L-DOPA methyl ester doses were selected as optimal and suboptimal doses (maximal and 50% of maximal responses, respectively). CE had no intrinsic effects on motor behavior regardless of the degree of parkinsonism (moderate or severe groups) or previous drug exposure ("de novo" or after L-DOPA priming). Initial CE administration did not affect development of L-DOPA antiparkinsonian responses. In coadministration trials, CE, in a dose-dependent manner, increased responses to L-DOPA (suboptimal doses). These effects were seen in both moderate and severely parkinsonian monkeys as a 30% increase of, predominantly, response duration with no effects on L-DOPA pharmacokinetics. CE did not modify levodopa-induced dyskinesias. These results suggest that selective cannabinoid CB1 antagonists may enhance the antiparkinsonian action of dopaminomimetics and possibly facilitate the use of lower doses, thereby reducing side effects.
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MESH Headings
- 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine
- Animals
- Antiparkinson Agents/adverse effects
- Antiparkinson Agents/pharmacokinetics
- Antiparkinson Agents/therapeutic use
- Azetidines/adverse effects
- Azetidines/pharmacokinetics
- Azetidines/therapeutic use
- Behavior, Animal/drug effects
- Disease Models, Animal
- Dose-Response Relationship, Drug
- Drug Therapy, Combination
- Dyskinesia, Drug-Induced/etiology
- Female
- Levodopa/adverse effects
- Levodopa/pharmacokinetics
- Levodopa/therapeutic use
- Macaca mulatta
- Male
- Molecular Structure
- Parkinson Disease/drug therapy
- Parkinson Disease/metabolism
- Parkinson Disease/physiopathology
- Receptor, Cannabinoid, CB1/antagonists & inhibitors
- Triazines/adverse effects
- Triazines/pharmacokinetics
- Triazines/therapeutic use
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Affiliation(s)
- Xuebing Cao
- Department of Neurology, Emory University, 6000 WMRB, 101 Woodruff Circle, Atlanta, GA 30322, USA
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132
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Burns HD, Van Laere K, Sanabria-Bohórquez S, Hamill TG, Bormans G, Eng WS, Gibson R, Ryan C, Connolly B, Patel S, Krause S, Vanko A, Van Hecken A, Dupont P, De Lepeleire I, Rothenberg P, Stoch SA, Cote J, Hagmann WK, Jewell JP, Lin LS, Liu P, Goulet MT, Gottesdiener K, Wagner JA, de Hoon J, Mortelmans L, Fong TM, Hargreaves RJ. [18F]MK-9470, a positron emission tomography (PET) tracer for in vivo human PET brain imaging of the cannabinoid-1 receptor. Proc Natl Acad Sci U S A 2007; 104:9800-5. [PMID: 17535893 PMCID: PMC1877985 DOI: 10.1073/pnas.0703472104] [Citation(s) in RCA: 238] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
[(18)F]MK-9470 is a selective, high-affinity, inverse agonist (human IC(50), 0.7 nM) for the cannabinoid CB1 receptor (CB1R) that has been developed for use in human brain imaging. Autoradiographic studies in rhesus monkey brain showed that [(18)F]MK-9470 binding is aligned with the reported distribution of CB1 receptors with high specific binding in the cerebral cortex, cerebellum, caudate/putamen, globus pallidus, substantia nigra, and hippocampus. Positron emission tomography (PET) imaging studies in rhesus monkeys showed high brain uptake and a distribution pattern generally consistent with that seen in the autoradiographic studies. Uptake was blocked by pretreatment with a potent CB1 inverse agonist, MK-0364. The ratio of total to nonspecific binding in putamen was 4-5:1, indicative of a strong specific signal that was confirmed to be reversible via displacement studies with MK-0364. Baseline PET imaging studies in human research subject demonstrated behavior of [(18)F]MK-9470 very similar to that seen in monkeys, with very good test-retest variability (7%). Proof of concept studies in healthy young male human subjects showed that MK-0364, given orally, produced a dose-related reduction in [(18)F]MK-9470 binding reflecting CB1R receptor occupancy by the drug. Thus, [(18)F]MK-9470 has the potential to be a valuable, noninvasive research tool for the in vivo study of CB1R biology and pharmacology in a variety of neuropsychiatric disorders in humans. In addition, it allows demonstration of target engagement and noninvasive dose-occupancy studies to aid in dose selection for clinical trials of CB1R inverse agonists.
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Affiliation(s)
- H Donald Burns
- Imaging Research, Merck Research Laboratories, West Point, PA 19486, USA.
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133
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Abstract
PURPOSE OF REVIEW Endocannabinoids are defined as endogenous agonists of cannabinoid receptors, that is, of the two G-protein-coupled receptors for the Cannabis psychoactive principle Delta-tetra-hydrocannabinol. Two such endogenous mediators have been most thoroughly studied so far: anandamide and 2-arachidonoylglycerol. Here we review the mechanisms for the regulation of their levels under physiological and pathological conditions, and recent findings on their role in disease. RECENT FINDINGS It is becoming increasingly clear that, although both anandamide and 2-arachidonoyl-glycerol are produced and degraded 'on demand', the levels of these two compounds appear to be regulated in different, and sometimes even opposing, ways, often using redundant molecular mechanisms. Alterations of endocannabinoid levels have been found in both animal models of pain, neurological and neurodegenerative states, gastrointestinal disorders and inflammatory conditions, and in blood, cerebrospinal fluid and bioptic samples from patients with various diseases. SUMMARY Endocannabinoid levels appear to be transiently elevated as an adaptive reaction to re-establish normal homeostasis when this is acutely and pathologically perturbed. In some chronic conditions, however, this system also contributes to the progress or symptoms of the disorder. As a consequence, new therapeutic drugs are being designed from both stimulants and blockers of endocannabinoid action.
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Affiliation(s)
- Vincenzo Di Marzo
- Endocannabinoid Research Group, Institute of Biomolecular Chemistry, Consiglio Nazionale delle Ricerche, Pozzuoli, Italy.
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134
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Fox SH, Lang AE, Brotchie JM. Translation of nondopaminergic treatments for levodopa-induced dyskinesia from MPTP-lesioned nonhuman primates to phase IIa clinical studies: keys to success and roads to failure. Mov Disord 2007; 21:1578-94. [PMID: 16874752 DOI: 10.1002/mds.20936] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Studies in MPTP-lesioned nonhuman primates have demonstrated the potential of nondopaminergic drugs in reducing the problems of levodopa-induced dyskinesia (LID). Here we review the process of translating findings from the monkey to man. Agents targeting glutamate, adensosine, noradrenaline, 5-hydroxytryptamine, cannabinoid, and opioid transmitter systems have been assessed for antidyskinetic potential in human studies. Eleven nondopaminergic drugs with antidyskinetic efficacy in the MPTP primate have been advanced to proof-of-concept phase IIa trials in PD patients (amantadine, istradefylline, idazoxan, fipamezole, sarizotan, quetiapine, clozapine, nabilone, rimonabant, naloxone, and naltrexone). For all six nondopaminergic transmitter systems reviewed, the MPTP-lesioned primate correctly predicted phase II efficacy of at least one drug. Of the 11 specific molecules tested in both monkeys and humans, 8 showed clear antidyskinetic properties in both human and monkey. In the instances where the primate studies did not, or did not consistently, predict the outcome of the human studies, the discrepancy may reflect limitations in the validity of the model or limitations in the design of either the clinical or the preclinical studies. We find that the major determinant of success in predicting efficacy is to ensure that primate studies are conducted in a statistically rigorous way and incorporate designs and outcome measures with clinical applicability. On the other hand, phase IIa trials should strive to replicate the preclinical study, especially in terms of protocol, drug dose equivalence, and outcome measure, so as to test the same hypothesis. Failure to meet these criteria carries the risk of false negative conclusions in phase IIa trials.
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Affiliation(s)
- Susan H Fox
- Movement Disorders Clinic, Toronto Western Hospital, Toronto, Ontario, Canada
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135
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Starowicz K, Nigam S, Di Marzo V. Biochemistry and pharmacology of endovanilloids. Pharmacol Ther 2007; 114:13-33. [PMID: 17349697 DOI: 10.1016/j.pharmthera.2007.01.005] [Citation(s) in RCA: 275] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2007] [Accepted: 01/24/2007] [Indexed: 11/28/2022]
Abstract
Endovanilloids are defined as endogenous ligands and activators of transient receptor potential (TRP) vanilloid type 1 (TRPV1) channels. The first endovanilloid to be identified was anandamide (AEA), previously discovered as an endogenous agonist of cannabinoid receptors. In fact, there are several similarities, in terms of opposing actions on the same intracellular signals, role in the same pathological conditions, and shared ligands and tissue distribution, between TRPV1 and cannabinoid CB(1) receptors. After AEA and some of its congeners (the unsaturated long chain N-acylethanolamines), at least 2 other families of endogenous lipids have been suggested to act as endovanilloids: (i) unsaturated long chain N-acyldopamines and (ii) some lipoxygenase (LOX) metabolites of arachidonic acid (AA). Here we discuss the mechanisms for the regulation of the levels of the proposed endovanilloids, as well as their TRPV1-mediated pharmacological actions in vitro and in vivo. Furthermore, we outline the possible pathological conditions in which endovanilloids, acting at sometimes aberrantly expressed TRPV1 receptors, might play a role.
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Affiliation(s)
- Katarzyna Starowicz
- Institute of Biomolecular Chemistry, Endocannabinoid Research Group, C.N.R., Pozzuoli, Naples, Italy
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136
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Basavarajappa BS. Neuropharmacology of the endocannabinoid signaling system-molecular mechanisms, biological actions and synaptic plasticity. Curr Neuropharmacol 2007; 5:81-97. [PMID: 18084639 PMCID: PMC2139910 DOI: 10.2174/157015907780866910] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2006] [Revised: 02/07/2007] [Accepted: 02/14/2007] [Indexed: 11/22/2022] Open
Abstract
The endocannabinoid signaling system is composed of the cannabinoid receptors; their endogenous ligands, the endocannabinoids; the enzymes that produce and inactivate the endocannabinoids; and the endocannabinoid transporters. The endocannabinoids are a new family of lipidic signal mediators, which includes amides, esters, and ethers of long-chain polyunsaturated fatty acids. Endocannabinoids signal through the same cell surface receptors that are targeted by Delta(9)-tetrahydrocannabinol (Delta(9)THC), the active principles of cannabis sativa preparations like hashish and marijuana. The biosynthetic pathways for the synthesis and release of endocannabinoids are still rather uncertain. Unlike neurotransmitter molecules that are typically held in vesicles before synaptic release, endocannabinoids are synthesized on demand within the plasma membrane. Once released, they travel in a retrograde direction and transiently suppress presynaptic neurotransmitter release through activation of cannabinoid receptors. The endocannabinoid signaling system is being found to be involved in an increasing number of pathological conditions. In the brain, endocannabinoid signaling is mostly inhibitory and suggests a role for cannabinoids as therapeutic agents in central nervous system (CNS) disease. Their ability to modulate synaptic efficacy has a wide range of functional consequences and provides unique therapeutic possibilities. The present review is focused on new information regarding the endocannabinoid signaling system in the brain. First, the structure, anatomical distribution, and signal transduction mechanisms of cannabinoid receptors are described. Second, the synthetic pathways of endocannabinoids are discussed, along with the putative mechanisms of their release, uptake, and degradation. Finally, the role of the endocannabinoid signaling system in the CNS and its potential as a therapeutic target in various CNS disease conditions, including alcoholism, are discussed.
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Affiliation(s)
- Balapal S Basavarajappa
- Division of Analytical Psychopharmacology, New York State Psychiatric Institute, New York, NY 10032, USA.
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137
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Abstract
Rimonabant is the first drug to target the endocannabinoid (CB) pathway by inhibiting the actions of anandamide and 2-archidonyl-glycerol on CB1 receptors. This review gives an overview of rimonabant and the CB system and how this system relates to obesity. Rimonabant blocks the central effects of this neurotransmitter pathway involved in obesity and weight control and also blocks the direct effects of CBs on adipocyte and hepatocyte metabolism. Blockade of CB1 receptors leads to a decrease in appetite and also has direct actions in adipose tissue and the liver to improve glucose, fat and cholesterol metabolism so improving insulin resistance, triglycerides and high-density lipoprotein cholesterol (HDL-C) and in some patients, blood pressure. The Rimonabant in Obesity (RIO) trials have shown that rimonabant induces weight loss > 5% in 30-40% of patients and > 10% in 10-20% above both a dietary run-in and long-term hypocaloric management over a 2 year period with a low level of drug-related side effects. Rimonabant therapy is associated with an extra 8-10% increase in HDL-C and a 10-30% reduction in triglycerides and improvements in insulin resistance, glycaemic control in patients with diabetes and also adipokines and cytokines including C-reactive protein over hypocaloric diet therapy. In addition rimonabant abolishes the weight gain associated with smoking cessation and improves the chances of quitting smoking. Thus rimonabant has major effects on both the metabolic syndrome and cardiovascular risk factors thus has the potential to reduce the risks of type 2 diabetes and cardiovascular disease associated with the cardiometabolic phenotype.
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Just A. Mechanisms of renal blood flow autoregulation: dynamics and contributions. Am J Physiol Regul Integr Comp Physiol 2006; 292:R1-17. [PMID: 16990493 DOI: 10.1152/ajpregu.00332.2006] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Autoregulation of renal blood flow (RBF) is caused by the myogenic response (MR), tubuloglomerular feedback (TGF), and a third regulatory mechanism that is independent of TGF but slower than MR. The underlying cause of the third regulatory mechanism remains unclear; possibilities include ATP, ANG II, or a slow component of MR. Other mechanisms, which, however, exert their action through modulation of MR and TGF are pressure-dependent change of proximal tubular reabsorption, resetting of RBF and TGF, as well as modulating influences of ANG II and nitric oxide (NO). MR requires < 10 s for completion in the kidney and normally follows first-order kinetics without rate-sensitive components. TGF takes 30-60 s and shows spontaneous oscillations at 0.025-0.033 Hz. The third regulatory component requires 30-60 s; changes in proximal tubular reabsorption develop over 5 min and more slowly for up to 30 min, while RBF and TGF resetting stretch out over 20-60 min. Due to these kinetic differences, the relative contribution of the autoregulatory mechanisms determines the amount and spectrum of pressure fluctuations reaching glomerular and postglomerular capillaries and thereby potentially impinge on filtration, reabsorption, medullary perfusion, and hypertensive renal damage. Under resting conditions, MR contributes approximately 50% to overall RBF autoregulation, TGF 35-50%, and the third mechanism < 15%. NO attenuates the strength, speed, and contribution of MR, whereas ANG II does not modify the balance of the autoregulatory mechanisms.
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Affiliation(s)
- Armin Just
- Department of Cell and Molecular Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7545, USA.
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Hardison S, Weintraub ST, Giuffrida A. Quantification of endocannabinoids in rat biological samples by GC/MS: technical and theoretical considerations. Prostaglandins Other Lipid Mediat 2006; 81:106-12. [PMID: 17085319 DOI: 10.1016/j.prostaglandins.2006.08.002] [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: 07/24/2006] [Revised: 08/11/2006] [Accepted: 08/18/2006] [Indexed: 10/24/2022]
Abstract
In the last several years, interest has increased significantly about the endocannabinoids anandamide and 2-arachidonylglycerol, two lipid messengers that activate cannabinoid receptors. Quantification of these compounds in biological samples presents numerous technical challenges. Because of their low abundance, endocannabinoids are usually quantified by isotope dilution assays using mass spectrometry coupled to either gas chromatography or high-performance liquid chromatography. Although endocannabinoid levels in biological fluids, such as plasma and cerebrospinal fluid, can be directly determined by these techniques, the complex lipid profile of brain tissue samples mandates purification of lipid extracts before GC/MS analysis; this step is not necessary when using HPLC/MS. We have found that when silica gel chromatography is used for endocannabinoid purification, poor recovery and loss of deuterium from the internal standards lead to inaccurate estimation of endocannabinoid levels. By contrast, purification strategies using C(18) solid-phase extraction permits precise and reproducible GC/MS quantification of endocannabinoids in tissue samples.
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Affiliation(s)
- Sarah Hardison
- Department of Pharmacology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
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Pacher P, Bátkai S, Kunos G. The endocannabinoid system as an emerging target of pharmacotherapy. Pharmacol Rev 2006; 58:389-462. [PMID: 16968947 PMCID: PMC2241751 DOI: 10.1124/pr.58.3.2] [Citation(s) in RCA: 1458] [Impact Index Per Article: 81.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The recent identification of cannabinoid receptors and their endogenous lipid ligands has triggered an exponential growth of studies exploring the endocannabinoid system and its regulatory functions in health and disease. Such studies have been greatly facilitated by the introduction of selective cannabinoid receptor antagonists and inhibitors of endocannabinoid metabolism and transport, as well as mice deficient in cannabinoid receptors or the endocannabinoid-degrading enzyme fatty acid amidohydrolase. In the past decade, the endocannabinoid system has been implicated in a growing number of physiological functions, both in the central and peripheral nervous systems and in peripheral organs. More importantly, modulating the activity of the endocannabinoid system turned out to hold therapeutic promise in a wide range of disparate diseases and pathological conditions, ranging from mood and anxiety disorders, movement disorders such as Parkinson's and Huntington's disease, neuropathic pain, multiple sclerosis and spinal cord injury, to cancer, atherosclerosis, myocardial infarction, stroke, hypertension, glaucoma, obesity/metabolic syndrome, and osteoporosis, to name just a few. An impediment to the development of cannabinoid medications has been the socially unacceptable psychoactive properties of plant-derived or synthetic agonists, mediated by CB(1) receptors. However, this problem does not arise when the therapeutic aim is achieved by treatment with a CB(1) receptor antagonist, such as in obesity, and may also be absent when the action of endocannabinoids is enhanced indirectly through blocking their metabolism or transport. The use of selective CB(2) receptor agonists, which lack psychoactive properties, could represent another promising avenue for certain conditions. The abuse potential of plant-derived cannabinoids may also be limited through the use of preparations with controlled composition and the careful selection of dose and route of administration. The growing number of preclinical studies and clinical trials with compounds that modulate the endocannabinoid system will probably result in novel therapeutic approaches in a number of diseases for which current treatments do not fully address the patients' need. Here, we provide a comprehensive overview on the current state of knowledge of the endocannabinoid system as a target of pharmacotherapy.
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Affiliation(s)
- Pál Pacher
- Laboratory of Physiological Studies, National Institute of Alcohol Abuse and Alcoholism, National Institutes of Health, 5625 Fishers Lane, Room 2S-24, Bethesda, MD 20892-9413, USA
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Alvira D, Tajes M, Verdaguer E, Acuña-Castroviejo D, Folch J, Camins A, Pallas M. Inhibition of the cdk5/p25 fragment formation may explain the antiapoptotic effects of melatonin in an experimental model of Parkinson's disease. J Pineal Res 2006; 40:251-8. [PMID: 16499562 DOI: 10.1111/j.1600-079x.2005.00308.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
In this study, the effects of melatonin on MPP+ -treated cerebellar granule neurons (CGNs) in culture were investigated. Results showed that MPP+ treatment significantly decreased cell viability and increased the apoptotic cell population at 24 and 48 hr. Calpain and caspase-3 activation was also determined, with results showing a strong increase in calpain (74%) and caspase 3 activity (70%), as measured by alpha-spectrin cleavage and fluorometric and colorimetric analysis, respectively. There are several studies suggesting that the activation of the cdk5/p35 pathway at its cleavage to cdk5/p25 may play a role in neuronal cell death in neurodegenerative diseases. Moreover, these studies indicate that this cleavage is mediated by calpains, and that MPP+ prompted an increase in cdk5 expression, as well as the cleavage of p35-p25, in a time-dependent manner. 1 mm Melatonin not only reduced the neurotoxic effects of MPP+ on cell viability, but also prevented apoptosis mediated by this Parkinsonian toxin in CGNs. 1 mm Melatonin reduced cdk5 expression, as well as the cleavage of p35-p25. These data indicate that melatonin possesses some neuro-protective properties against MPP+ -induced apoptosis. Moreover, these data suggest that the calpain/cdk5 signaling cascade has a potential role in the MPP+ -mediated apoptotic process in CGNs.
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Affiliation(s)
- Daniel Alvira
- Unitat de Farmacologia i Farmacognòsia, Facultat de Farmacia, Universitat de Barcelona, Nucli Universitari de Pedralbes, Barcelona, Spain
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Tzavara ET, Li DL, Moutsimilli L, Bisogno T, Di Marzo V, Phebus LA, Nomikos GG, Giros B. Endocannabinoids activate transient receptor potential vanilloid 1 receptors to reduce hyperdopaminergia-related hyperactivity: therapeutic implications. Biol Psychiatry 2006; 59:508-15. [PMID: 16199010 DOI: 10.1016/j.biopsych.2005.08.019] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2005] [Revised: 07/26/2005] [Accepted: 08/09/2005] [Indexed: 10/25/2022]
Abstract
BACKGROUND Knockout (KO) mice invalidated for the dopamine transporter (DAT) constitute a powerful animal model of neurobiological alterations associated with hyperdopaminergia relevant to schizophrenia and attention-deficit/hyperactivity disorder (ADHD). METHODS Because of continuously increasing evidence for a neuromodulatory role of endocannabinoids in dopamine-related pathophysiological responses, we assessed endocannabinoid signaling in DAT KO mice and evaluated the ability of endocannabinoid ligands to normalize behavioral deficits, namely spontaneous hyperlocomotion in these mice. RESULTS In DAT KO mice, we found markedly reduced anandamide levels, specifically in striatum, the dopamine nerve terminal region. Furthermore, three distinct indirect endocannabinoid agonists, the selective anandamide reuptake inhibitors AM404 and VDM11 and the fatty acid amidohydrolase inhibitor AA5HT, attenuated spontaneous hyperlocomotion in DAT KO mice. The hypolocomotor effects of AM404, VDM11, and AA5HT were significantly attenuated by co-administration of the transient receptor potential vanilloid 1 (TRPV1) antagonist capsazepine but not the selective cannabinoid type 1 (CB1)receptor antagonist AM251. Interestingly, TRPV1 binding was increased in the striatum of DAT KO mice, while CB1 receptor binding was unaffected. CONCLUSIONS These data indicate a dysregulated striatal endocannabinoid neurotransmission associated with hyperdopaminergic state. Restoring endocannabinoid homeostasis in active synapses might constitute an alternative therapeutic strategy for disorders associated with hyperdopaminergia. In this process, TRPV1 receptors seem to play a key role and represent a novel promising pharmacological target.
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Affiliation(s)
- Eleni T Tzavara
- INSERM U-513, Neurobiology and Psychiatry, Université de Médecine, Créteil, France
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Gomez-Ramirez J, Johnston TH, Visanji NP, Fox SH, Brotchie JM. Histamine H3 receptor agonists reduce L-dopa-induced chorea, but not dystonia, in the MPTP-lesioned nonhuman primate model of Parkinson's disease. Mov Disord 2006; 21:839-46. [PMID: 16532454 DOI: 10.1002/mds.20828] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
L-dopa-induced dyskinesia (LID) remains a major complication of the treatment of Parkinson's disease. The neural mechanisms underlying LID are thought to involve overactivity of striatal glutamatergic neurotransmission, with resultant underactivation of the output regions of the basal ganglia. Histamine H3 heteroreceptors can reduce glutamate and gamma-aminobutyric acid (GABA) transmission in the striatum and substantia nigra reticulata, respectively. Thus, we tested whether the histamine H3 receptor agonists immepip and imetit can alleviate LID in the MPTP-lesioned marmoset model of Parkinson's disease. Coadministration of immepip (1 mg/kg) with L-dopa (15 mg/kg) was associated with significantly less total dyskinesia than L-dopa alone. When dyskinesia was separately rated as chorea and dystonia, coadministration of L-dopa with either immepip or imetit (both 10 mg/kg) significantly reduced chorea but had no effect on dystonia. The antidyskinetic actions of the H3 agonists were not accompanied by alteration of the antiparkinsonian actions of L-dopa. However, immepip (10 mg/kg), when administered as monotherapy, significantly increased parkinsonian disability compared to vehicle. Overall, the results obtained in this study suggest that histamine H3 receptors may be involved in the neural mechanisms underlying L-dopa-induced dyskinesia in Parkinson's disease.
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Affiliation(s)
- Jordi Gomez-Ramirez
- Toronto Western Research Institute, Toronto Western Hospital, University Health Network, Toronto, Ontario, Canada
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Abstract
Although used for more than 4000 years for recreational and medicinal purposes, Cannabis and its best-known pharmacologically active constituents, the cannabinoids, became a protagonist in medical research only recently. This revival of interest is explained by the finding in the 1990s of the mechanism of action of the main psychotropic cannabinoid, Delta9-tetrahydrocannabinol (THC), which acts through specific membrane receptors, the cannabinoid receptors. The molecular characterization of these receptors allowed the development of synthetic molecules with cannabinoid and noncannabinoid structure and with higher selectivity, metabolic stability, and efficacy than THC, as well as the development of antagonists that have already found pharmaceutical application. The finding of endogenous agonists at these receptors, the endocannabinoids, opened new therapeutic possibilities through the modulation of the activity of cannabinoid receptors by targeting the biochemical mechanisms controlling endocannabinoid tissue levels.
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Affiliation(s)
- Vincenzo Di Marzo
- Endocannabinoid Research Group, Institutes of Biomolecular Chemistry, National Research Council, Via Campi Flegrei 34, Comprensorio Olivetti, 80078 Pozzuoli, Naples, Italy.
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