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Zhan X, Do LV, Zou L, Zhan RS, Jones M, Nawaz S, Manaye K. Harmaline toxicity on dorsal striatal neurons and its role in tremor. Neurotoxicology 2023; 99:152-161. [PMID: 37838252 DOI: 10.1016/j.neuro.2023.10.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 08/28/2023] [Accepted: 10/08/2023] [Indexed: 10/16/2023]
Abstract
Harmaline is one of the β-carboline derivative compounds that is widely distributed in the food chain and human tissues. Harmine, a dehydrogenated form of harmaline, appeared to have a higher concentration in the brain, and appeared to be elevated in essential tremor (ET) and Parkinson's disease. Exogenous harmaline exposure in high concentration has myriad consequences, including inducing tremor, and causing neurodegeneration of Purkinje cells in the cerebellum. Harmaline-induced tremor is an established animal model for human ET, but its underlying mechanism is still controversial. One hypothesis posits that the inferior olive-cerebellum pathway is involved, and CaV3.1 T-type Ca2+ channel is a critical target of action. However, accumulating evidence indicates that tremor can be generated without disturbing T-type channels. This implies that additional neural circuits or molecular targets are involved. Using in vitro slice Ca2+-imaging and patch clamping, we demonstrated that harmaline reduced intracellular Ca2+ and suppressed depolarization-induced spiking activity of medium spiny striatal neurons (MSN), and this effect of harmaline can be partially attenuated by sulpiride (5 µM). In addition, the frequencies of spontaneous excitatory post-synaptic currents (sEPSCs) on MSNs were also significantly attenuated. Furthermore, the induced tremor in C57BL/6 J mice by harmaline injections (i.p. 12.5-18 mg/kg) was also shown to be attenuated by sulpiride (20 mg/kg). This series of experiments suggests that the dorsal striatum is a site of harmaline toxic action and might contribute to tremor generation. The findings also provide evidence that D2 signaling might be a part of the mechanism underlying essential tremor.
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Affiliation(s)
- Xiping Zhan
- Department of Physiology and Biophysics, College of Medicine, Howard University, Washington, DC 20059, USA; Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Ly V Do
- Department of Physiology and Biophysics, College of Medicine, Howard University, Washington, DC 20059, USA
| | - Li Zou
- Department of Physiology and Biophysics, College of Medicine, Howard University, Washington, DC 20059, USA
| | - Ryan Shu Zhan
- Department of Physiology and Biophysics, College of Medicine, Howard University, Washington, DC 20059, USA
| | - Michael Jones
- Department of Physiology and Biophysics, College of Medicine, Howard University, Washington, DC 20059, USA
| | - Saba Nawaz
- Department of Physiology and Biophysics, College of Medicine, Howard University, Washington, DC 20059, USA
| | - Kebreten Manaye
- Department of Physiology and Biophysics, College of Medicine, Howard University, Washington, DC 20059, USA
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Louis ED, Martuscello RT, Gionco JT, Hartstone WG, Musacchio JB, Portenti M, McCreary M, Kuo SH, Vonsattel JPG, Faust PL. Histopathology of the cerebellar cortex in essential tremor and other neurodegenerative motor disorders: comparative analysis of 320 brains. Acta Neuropathol 2023; 145:265-283. [PMID: 36607423 PMCID: PMC10461794 DOI: 10.1007/s00401-022-02535-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/14/2022] [Accepted: 12/22/2022] [Indexed: 01/07/2023]
Abstract
In recent years, numerous morphologic changes have been identified in the essential tremor (ET) cerebellar cortex, distinguishing ET from control brains. These findings have not been fully contextualized within a broader degenerative disease spectrum, thus limiting their interpretability. Building off our prior study and now doubling the sample size, we conducted comparative analyses in a postmortem series of 320 brains on the severity and patterning of cerebellar cortex degenerative changes in ET (n = 100), other neurodegenerative disorders of the cerebellum [spinocerebellar ataxias (SCAs, n = 47, including 13 SCA3 and 34 SCA1, 2, 6, 7, 8, 14); Friedreich's ataxia (FA, n = 13); multiple system atrophy (MSA), n = 29], and other disorders that may involve the cerebellum [Parkinson's disease (PD), n = 62; dystonia, n = 19] versus controls (n = 50). We generated data on 37 quantitative morphologic metrics, grouped into 8 broad categories: Purkinje cell (PC) loss, heterotopic PCs, PC dendritic changes, PC axonal changes (torpedoes), PC axonal changes (other than torpedoes), PC axonal changes (torpedo-associated), basket cell axonal hypertrophy, and climbing fiber-PC synaptic changes. Principal component analysis of z scored raw data across all diagnoses (11,651 data items) revealed that diagnostic groups were not uniform with respect to pathology. Dystonia and PD each differed from controls in only 4/37 and 5/37 metrics, respectively, whereas ET differed in 21, FA in 10, SCA3 in 10, MSA in 21, and SCA1/2/6/7/8/14 in 27. Pathological changes were generally on the milder end of the degenerative spectrum in ET, FA and SCA3, and on the more severe end of that spectrum in SCA1/2/6/7/8/14. Comparative analyses across morphologic categories demonstrated differences in relative expression, defining distinctive patterns of changes in these groups. In summary, we present a robust and reproducible method that identifies somewhat distinctive signatures of degenerative changes in the cerebellar cortex that mark each of these disorders.
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Affiliation(s)
- Elan D Louis
- Department of Neurology, University of Texas Southwestern, 5323 Harry Hines Blvd, Dallas, TX, 75390-8813, USA.
| | - Regina T Martuscello
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center and the New York Presbyterian Hospital, New York, NY, USA
| | - John T Gionco
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center and the New York Presbyterian Hospital, New York, NY, USA
| | - Whitney G Hartstone
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center and the New York Presbyterian Hospital, New York, NY, USA
| | - Jessica B Musacchio
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center and the New York Presbyterian Hospital, New York, NY, USA
| | - Marisa Portenti
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center and the New York Presbyterian Hospital, New York, NY, USA
| | - Morgan McCreary
- Department of Neurology, University of Texas Southwestern, 5323 Harry Hines Blvd, Dallas, TX, 75390-8813, USA
| | - Sheng-Han Kuo
- Department of Neurology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Jean-Paul G Vonsattel
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center and the New York Presbyterian Hospital, New York, NY, USA
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, USA
| | - Phyllis L Faust
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center and the New York Presbyterian Hospital, New York, NY, USA
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Kosmowska B, Paleczna M, Biała D, Kadłuczka J, Wardas J, Witkin JM, Cook JM, Sharmin D, Marcinkowska M, Kuter KZ. GABA-A Alpha 2/3 but Not Alpha 1 Receptor Subunit Ligand Inhibits Harmaline and Pimozide-Induced Tremor in Rats. Biomolecules 2023; 13:biom13020197. [PMID: 36830567 PMCID: PMC9953228 DOI: 10.3390/biom13020197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 01/11/2023] [Accepted: 01/15/2023] [Indexed: 01/20/2023] Open
Abstract
Treatment of tremors, such as in essential tremor (ET) and Parkinson's disease (PD) is mostly ineffective. Exact tremor pathomechanisms are unknown and relevant animal models are missing. GABA-A receptor is a target for tremorolytic medications, but current non-selective drugs produce side effects and have safety liabilities. The aim of this study was a search for GABA-A subunit-specific tremorolytics using different tremor-generating mechanisms. Two selective positive allosteric modulators (PAMs) were tested. Zolpidem, targeting GABA-A α1, was not effective in models of harmaline-induced ET, pimozide- or tetrabenazine-induced tremulous jaw movements (TJMs), while the novel GABA-A α2/3 selective MP-III-024 significantly reduced both the harmaline-induced ET tremor and pimozide-induced TJMs. While zolpidem decreased the locomotor activity of the rats, MP-III-024 produced small increases. These results provide important new clues into tremor suppression mechanisms initiated by the enhancement of GABA-driven inhibition in pathways controlled by α2/3 but not α1 containing GABA-A receptors. Tremor suppression by MP-III-024 provides a compelling reason to consider selective PAMs targeting α2/3-containing GABA-A receptors as novel therapeutic drug targets for ET and PD-associated tremor. The possibility of the improved tolerability and safety of this mechanism over non-selective GABA potentiation provides an additional rationale to further pursue the selective α2/3 hypothesis.
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Affiliation(s)
- Barbara Kosmowska
- Department of Neuropsychopharmacology, Maj Institute of Pharmacology, Polish Academy of Sciences, 12 Smetna St., 31-343 Krakow, Poland
| | - Martyna Paleczna
- Department of Neuropsychopharmacology, Maj Institute of Pharmacology, Polish Academy of Sciences, 12 Smetna St., 31-343 Krakow, Poland
| | - Dominika Biała
- Department of Neuropsychopharmacology, Maj Institute of Pharmacology, Polish Academy of Sciences, 12 Smetna St., 31-343 Krakow, Poland
| | - Justyna Kadłuczka
- Department of Neuropsychopharmacology, Maj Institute of Pharmacology, Polish Academy of Sciences, 12 Smetna St., 31-343 Krakow, Poland
| | - Jadwiga Wardas
- Department of Neuropsychopharmacology, Maj Institute of Pharmacology, Polish Academy of Sciences, 12 Smetna St., 31-343 Krakow, Poland
| | - Jeffrey M. Witkin
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA
- RespireRx Pharmaceuticals Inc., Glen Rock, NJ 07452, USA
| | - James M. Cook
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA
- RespireRx Pharmaceuticals Inc., Glen Rock, NJ 07452, USA
| | - Dishary Sharmin
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA
| | - Monika Marcinkowska
- Department of Pharmaceutical Chemistry, Jagiellonian University, Medical College, 9 Medyczna St., 30-688 Krakow, Poland
| | - Katarzyna Z. Kuter
- Department of Neuropsychopharmacology, Maj Institute of Pharmacology, Polish Academy of Sciences, 12 Smetna St., 31-343 Krakow, Poland
- Correspondence: ; Tel.: +48-12-662-32-26
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Abstract
Harman and norharman, two neuroactive β-carbolines, are present in several plants and in thermally processed foods. They exhibited a wide spectrum of biological and pharmacological effects, including antioxidant, neuroprotective, and anti-inflammatory effects. In this article, we review the progress of recent research on the presence of these compounds in food, as well as their various biological and neuroactive properties. Our findings strongly suggest that some foods, especially coffee, can act as a rich source of β-carbolines, which may possibly be associated with a reduced risk for serious neurodegenerative diseases, such as Parkinson's and Alzheimer's.
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Affiliation(s)
- Paulina Piechowska
- Faculty of Food Science and Nutrition, Poznań University of Life Sciences, Wojska Polskiego 28, 60-637 Poznań, Poland.
| | - Renata Zawirska-Wojtasiak
- Faculty of Food Science and Nutrition, Poznań University of Life Sciences, Wojska Polskiego 28, 60-637 Poznań, Poland.
| | - Sylwia Mildner-Szkudlarz
- Faculty of Food Science and Nutrition, Poznań University of Life Sciences, Wojska Polskiego 28, 60-637 Poznań, Poland.
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Ohno Y, Shimizu S, Tatara A, Imaoku T, Ishii T, Sasa M, Serikawa T, Kuramoto T. Hcn1 is a tremorgenic genetic component in a rat model of essential tremor. PLoS One 2015; 10:e0123529. [PMID: 25970616 PMCID: PMC4430019 DOI: 10.1371/journal.pone.0123529] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 02/18/2015] [Indexed: 01/12/2023] Open
Abstract
Genetic factors are thought to play a major role in the etiology of essential tremor (ET); however, few genetic changes that induce ET have been identified to date. In the present study, to find genes responsible for the development of ET, we employed a rat model system consisting of a tremulous mutant strain, TRM/Kyo (TRM), and its substrain TRMR/Kyo (TRMR). The TRM rat is homozygous for the tremor (tm) mutation and shows spontaneous tremors resembling human ET. The TRMR rat also carries a homozygous tm mutation but shows no tremor, leading us to hypothesize that TRM rats carry one or more genes implicated in the development of ET in addition to the tm mutation. We used a positional cloning approach and found a missense mutation (c. 1061 C>T, p. A354V) in the hyperpolarization-activated cyclic nucleotide-gated 1 channel (Hcn1) gene. The A354V HCN1 failed to conduct hyperpolarization-activated currents in vitro, implicating it as a loss-of-function mutation. Blocking HCN1 channels with ZD7288 in vivo evoked kinetic tremors in nontremulous TRMR rats. We also found neuronal activation of the inferior olive (IO) in both ZD7288-treated TRMR and non-treated TRM rats and a reduced incidence of tremor in the IO-lesioned TRM rats, suggesting a critical role of the IO in tremorgenesis. A rat strain carrying the A354V mutation alone on a genetic background identical to that of the TRM rats showed no tremor. Together, these data indicate that body tremors emerge when the two mutant loci, tm and Hcn1A354V, are combined in a rat model of ET. In this model, HCN1 channels play an important role in the tremorgenesis of ET. We propose that oligogenic, most probably digenic, inheritance is responsible for the genetic heterogeneity of ET.
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Affiliation(s)
- Yukihiro Ohno
- Laboratory of Pharmacology, Osaka University of Pharmaceutical Sciences, Takatsuki, 569–1094, Japan
| | - Saki Shimizu
- Laboratory of Pharmacology, Osaka University of Pharmaceutical Sciences, Takatsuki, 569–1094, Japan
| | - Ayaka Tatara
- Laboratory of Pharmacology, Osaka University of Pharmaceutical Sciences, Takatsuki, 569–1094, Japan
| | - Takuji Imaoku
- Laboratory of Pharmacology, Osaka University of Pharmaceutical Sciences, Takatsuki, 569–1094, Japan
| | - Takahiro Ishii
- Department of Physiology and Neurobiology, Graduate School of Medicine, Kyoto University, Kyoto, 606–8501, Japan
| | | | - Tadao Serikawa
- Laboratory of Pharmacology, Osaka University of Pharmaceutical Sciences, Takatsuki, 569–1094, Japan
- Institute of Laboratory Animals, Graduate School of Medicine, Kyoto University, Kyoto, 606–8501, Japan
| | - Takashi Kuramoto
- Institute of Laboratory Animals, Graduate School of Medicine, Kyoto University, Kyoto, 606–8501, Japan
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Kuo SH, Tang G, Ma K, Babij R, Cortes E, Vonsattel JPG, Faust PL, Sulzer D, Louis ED. Macroautophagy abnormality in essential tremor. PLoS One 2012; 7:e53040. [PMID: 23300858 PMCID: PMC3531444 DOI: 10.1371/journal.pone.0053040] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Accepted: 11/22/2012] [Indexed: 11/19/2022] Open
Abstract
Macroautophagy is a cellular mechanism for the clearance of protein aggregates and damaged organelles. Impaired macroautophagy has been observed in neurodegenerative disorders. We investigated the macroautophagy pathway in essential tremor (ET) cases compared to age-matched controls. We analyzed microtubule-associated protein light chain 3-II (LC3-II), S6K, phosphorylated S6K, beclin-1, and mitochondrial membrane proteins levels by Western blot in the post-mortem cerebellum of 10 ET cases and 11 controls. We also performed immunohistochemistry in 12 ET cases and 13 controls to quantify LC3 clustering in Purkinje cells (PCs). LC3-II protein levels were significantly lower in ET cases vs. controls on Western blot (0.84±0.14 vs. 1.00±0.14, p = 0.02), and LC3-II clustering in PCs by immunohistochemistry was significantly lower in ET cases vs. controls (2.03±3.45 vs. 8.80±9.81, p = 0.03). In ET cases, disease duration was inversely correlated with LC3-II protein level (r = −0.64, p = 0.046). We found that mitochondrial membrane proteins were accumulated in ET (TIM23: 1.36±0.11 in ET cases vs. 1.00±0.08 in controls, p = 0.02; TOMM20: 1.63±0.87 in ET cases vs. 1.00±0.14 in controls, p = 0.03). Beclin-1, which is involved in macroautophagy, was strikingly deficient in ET (0.42±0.13 vs. 1.00±0.35, p<0.001). Decreased macroautophagy was observed in the ET cerebellum, and this could be due to a decrease in beclin-1 levels, which subsequently lead to mitochondrial accumulation as a result of autophagic failure. This provides a possible means by which perturbed macroautophagy could contribute to PC pathology in ET.
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Affiliation(s)
- Sheng-Han Kuo
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, New York, United States of America
| | - Guomei Tang
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, New York, United States of America
| | - Karen Ma
- GH Sergievsky Center, College of Physicians and Surgeons, Columbia University, New York, New York, United States of America
| | - Rachel Babij
- GH Sergievsky Center, College of Physicians and Surgeons, Columbia University, New York, New York, United States of America
| | - Etty Cortes
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, New York, New York, United States of America
- Department of Pathology and Cell Biology, Columbia University Medical Center and the New York Presbyterian Hospital, New York, New York, United States of America
| | - Jean-Paul G. Vonsattel
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, New York, New York, United States of America
- Department of Pathology and Cell Biology, Columbia University Medical Center and the New York Presbyterian Hospital, New York, New York, United States of America
| | - Phyllis L. Faust
- Department of Pathology and Cell Biology, Columbia University Medical Center and the New York Presbyterian Hospital, New York, New York, United States of America
| | - David Sulzer
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, New York, United States of America
| | - Elan D. Louis
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, New York, United States of America
- GH Sergievsky Center, College of Physicians and Surgeons, Columbia University, New York, New York, United States of America
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, New York, New York, United States of America
- Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, New York, United States of America
- * E-mail:
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Gironell A, Figueiras FP, Pagonabarraga J, Herance JR, Pascual-Sedano B, Trampal C, Gispert JD. Gaba and serotonin molecular neuroimaging in essential tremor: a clinical correlation study. Parkinsonism Relat Disord 2012; 18:876-80. [PMID: 22595620 DOI: 10.1016/j.parkreldis.2012.04.024] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 04/13/2012] [Accepted: 04/20/2012] [Indexed: 11/18/2022]
Abstract
BACKGROUND Essential tremor is the most common movement disorder in adults, but its exact etiology and pathophysiology are still not fully understood. There is some consensus, however, about the involvement of the cerebellum and accumulating evidence points towards a dysfunction of the gabaergic system. We hypothesize that the serotonin neurotransmission system may also play a role as it does in tremor in Parkinson disease. This study aimed to investigate the association between the severity of tremor symptoms and the gabaergic and serotoninergic neurotransmission systems in essential tremor. MATERIAL AND METHODS We measured the tremor clinical rating scale score and acquired DASB and Flumazenil PET scans in 10 patients who presented with essential tremor at different stages of clinical severity. Statistically significant correlations were sought between the scale scores and parametric binding potential images. RESULTS The correlation analysis of cerebellar Flumazenil uptake and tremor clinical rating scale scores reached statistical significance (R2 = 0.423, p = 0.041), whereas no association was detected in the DASB scans. CONCLUSIONS The severity of tremor correlated with the abnormalities found in GABA receptor binding, suggesting a primary gabaergic deficiency or a functional abnormality at the level of GABA(A) receptor subtypes. These results may assist in the rational development of new pharmacological treatments for essential tremor.
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Affiliation(s)
- A Gironell
- Movement Disorders Unit, Department of Neurology, Sant Pau Hospital, Autonomous University of Barcelona, Catalonia, Spain.
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Louis ED, Zheng W. Beta-carboline alkaloids and essential tremor: exploring the environmental determinants of one of the most prevalent neurological diseases. ScientificWorldJournal 2010; 10:1783-94. [PMID: 20842322 PMCID: PMC3700397 DOI: 10.1100/tsw.2010.159] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2010] [Revised: 07/15/2010] [Accepted: 07/15/2010] [Indexed: 12/13/2022] Open
Abstract
Essential tremor (ET) is among the most prevalent neurological diseases, yet its etiology is not well understood. Susceptibility genotypes undoubtedly underlie many ET cases, although no genes have been identified thus far. Environmental factors are also likely to contribute to the etiology of ET. Harmane (1-methyl-9H-pyrido[3,4-beta]indole) is a potent, tremor-producing beta-carboline alkaloid, and emerging literature has provided initial links between this neurotoxin and ET. In this report, we review this literature. Two studies, both in New York, have demonstrated higher blood harmane levels in ET cases than controls and, in one study, especially high levels in familial ET cases. Replication studies of populations outside of New York and studies of brain harmane levels in ET have yet to be undertaken. A small number of studies have explored several of the biological correlates of exposure to harmane in ET patients. Studies of the mechanisms of this putative elevation of harmane in ET have explored the role of increased dietary consumption, finding weak evidence of increased exogenous intake in male ET cases, and other studies have found initial evidence that the elevated harmane in ET might be due to a hereditarily reduced capacity to metabolize harmane to harmine (7-methoxy-1-methyl-9H-pyrido[3,4-beta]-indole). Studies of harmane and its possible association with ET have been intriguing. Additional studies are needed to establish more definitively whether these toxic exposures are associated with ET and are of etiological importance.
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Affiliation(s)
- Elan D Louis
- GH Sergievsky Center, Columbia University, New York, USA.
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9
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Abstract
PURPOSE OF REVIEW Elucidating the genetic background of Parkinson disease and essential tremor is crucial to understand the pathogenesis and improve diagnostic and therapeutic strategies. RECENT FINDINGS A number of approaches have been applied including familial and association studies, and studies of gene expression profiles to identify genes involved in susceptibility to Parkinson disease. These studies have nominated a number of candidate Parkinson disease genes and novel loci including Omi/HtrA2, GIGYF2, FGF20, PDXK, EIF4G1 and PARK16. A recent notable finding has been the confirmation for the role of heterozygous mutations in glucocerebrosidase (GBA) as risk factors for Parkinson disease. Finally, association studies have nominated genetic variation in the leucine-rich repeat and Ig containing 1 gene (LINGO1) as a risk for both Parkinson disease and essential tremor, providing the first genetic evidence of a link between the two conditions. SUMMARY Although undoubtedly genes remain to be identified, considerable progress has been achieved in the understanding of the genetic basis of Parkinson disease. This same effort is now required for essential tremor. The use of next-generation high-throughput sequencing and genotyping technologies will help pave the way for future insight leading to advances in diagnosis, prevention and cure.
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Affiliation(s)
- Christian Wider
- Division of Neurology, Department of Clinical Neuroscience, Centre Hospitalier Universitaire Vaudois (CHUV), Lausanne, Switzerland.
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Handforth A, Homanics GE, Covey DF, Krishnan K, Lee JY, Sakimura K, Martin FC, Quesada A. T-type calcium channel antagonists suppress tremor in two mouse models of essential tremor. Neuropharmacology 2010; 59:380-7. [PMID: 20547167 DOI: 10.1016/j.neuropharm.2010.05.012] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2009] [Revised: 05/14/2010] [Accepted: 05/24/2010] [Indexed: 11/17/2022]
Abstract
Essential tremor is a common disorder that lacks molecular targets for therapeutic development. T-type calcium channel activation has been postulated to underlie rhythmicity in the olivo-cerebellar system that is implicated in essential tremor. We therefore tested whether compounds that antagonize T-type calcium channel currents suppress tremor in two mouse models that possess an essential tremor-like pharmacological response profile. Tremor was measured using digitized spectral motion power analysis with harmaline-induced tremor and in the GABA(A) receptor α1 subunit-null model. Mice were given ethosuximide, zonisamide, the neuroactive steroid (3β,5α,17β)-17-hydroxyestrane-3-carbonitrile (ECN), the 3,4-dihydroquinazoline derivative KYS05064, the mibefradil derivative NNC 55-0396, or vehicle. In non-sedating doses, each compound reduced harmaline-induced tremor by at least 50% (range of maximal suppression: 53-81%), and in the GABA(A) α1-null model by at least 70% (range 70-93%). Because the T-type calcium channel Cav3.1 is the dominant subtype expressed in the inferior olive, we assessed the tremor response of Cav3.1-deficient mice to harmaline, and found that null and heterozygote mice exhibit as much tremor as wild-type mice. In addition, ECN and NNC 55-0396 suppressed harmaline tremor as well in Cav3.1-null mice as in wild-type mice. The finding that five T-type calcium antagonists suppress tremor in two animal tremor models suggests that T-type calcium channels may be an appropriate target for essential tremor therapy development. It is uncertain whether medications developed to block only the Cav3.1 subtype would exhibit efficacy.
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Affiliation(s)
- Adrian Handforth
- Neurology Service (W127), Veterans Affairs Greater Los Angeles Healthcare System, 11301 Wilshire Blvd, Los Angeles, CA 90073, USA.
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Schneider SA, Edwards MJ, Mir P, Cordivari C, Hooker J, Dickson J, Quinn N, Bhatia KP. Patients with adult-onset dystonic tremor resembling parkinsonian tremor have scans without evidence of dopaminergic deficit (SWEDDs). Mov Disord 2008; 22:2210-5. [PMID: 17712858 DOI: 10.1002/mds.21685] [Citation(s) in RCA: 190] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
We present the clinical details and dopamine transporter SPECT scan results of 10 patients with arm tremor, including a rest component and reduced arm swing on the affected side, in whom the possibility of PD had been raised. All patients had signs of dystonia or components of their arm tremor that were compatible with dystonic tremor, and none had true akinesia with fatiguing or decrement, even after a mean follow-up period of 5.8 years. All patients had normal dopamine transporter SPECT scans. Clinicians should be aware that primary adult-onset dystonia can present with an asymmetric resting arm tremor, with impaired arm swing and sometimes also facial hypomimia or a jaw tremor, but without evidence of true akinesia. Given the important consequences of misdiagnosing such patients as PD, in cases with diagnostic uncertainty functional imaging should be considered. Among patients suspected of PD, dystonic tremor may be one cause of SWEDDs (Scans Without Evidence of Dopaminergic Deficit).
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Affiliation(s)
- Susanne A Schneider
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, Queen Square, London WC1N 3BG, United Kingdom
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12
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Jeanneteau F, Funalot B, Jankovic J, Deng H, Lagarde JP, Lucotte G, Sokoloff P. A functional variant of the dopamine D3 receptor is associated with risk and age-at-onset of essential tremor. Proc Natl Acad Sci U S A 2006; 103:10753-8. [PMID: 16809426 PMCID: PMC1502303 DOI: 10.1073/pnas.0508189103] [Citation(s) in RCA: 154] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Familial essential tremor (ET), the most common inherited movement disorder, is generally transmitted as an autosomal dominant trait. A genome-wide scan for ET revealed one major locus on chromosome 3q13. Here, we report that the Ser9Gly variant in the dopamine D(3) receptor gene (DRD3), localized on 3q13.3, is associated and cosegregates with familial ET in 23 out of 30 French families. Sequencing revealed no other nonsynonymous variants in the DRD3-coding sequence and in the first 871 bp of the 5' flanking region. Moreover, Gly-9 homozygous patients presented with more severe and/or earlier onset forms of the disease than heterozygotes. A replication study comparing 276 patients with ET and 184 normal controls confirmed the association of the Gly-9 variant with risk and age-at-onset of ET. In human embryonic kidney (HEK) 293-transfected cells, the Gly-9 variant did not differ from the Ser-9 variant with respect to glycosylation and to anterograde and retrograde trafficking, but dopamine had an affinity that was four to five times higher. With the Gly-9 variant, the dopamine-mediated cAMP response was increased, and the mitogen-associated protein kinase (MAPK) signal was prolonged, as compared with the Ser-9 variant. The gain-of-function produced by the Gly-9 variant may explain why drugs active against tremor in Parkinson's disease (PD) are usually not effective in the treatment of ET and suggests that DRD3 partial agonists or antagonists should be considered as novel therapeutic options for patients with ET.
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Affiliation(s)
- Freddy Jeanneteau
- *Institut National de la Santé et de la Recherche Médicale, Unité de Neurobiologie et Pharmacologie Moléculaire, U573, Centre Paul Broca, 75014 Paris, France
| | - Benoît Funalot
- *Institut National de la Santé et de la Recherche Médicale, Unité de Neurobiologie et Pharmacologie Moléculaire, U573, Centre Paul Broca, 75014 Paris, France
- Service de Neurologie, Centre Hospitalier Ste-Anne, 75014 Paris, France
| | - Joseph Jankovic
- Department of Neurology, Baylor College of Medicine, Houston, TX 77030
| | - Hao Deng
- Department of Neurology, Baylor College of Medicine, Houston, TX 77030
| | - Jean-Pierre Lagarde
- Laboratoire de Génétique Moléculaire, Hôpital de la Pitié-Salpétrière, 75013 Paris, France; and
| | - Gérard Lucotte
- Centre de Neurogénétique Moléculaire, 75005 Paris, France
| | - Pierre Sokoloff
- *Institut National de la Santé et de la Recherche Médicale, Unité de Neurobiologie et Pharmacologie Moléculaire, U573, Centre Paul Broca, 75014 Paris, France
- To whom correspondence should be addressed. E-mail:
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Deng H, Xie WJ, Le WD, Huang MS, Jankovic J. Genetic analysis of the GABRA1 gene in patients with essential tremor. Neurosci Lett 2006; 401:16-9. [PMID: 16530959 DOI: 10.1016/j.neulet.2006.02.066] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2005] [Revised: 02/20/2006] [Accepted: 02/22/2006] [Indexed: 11/22/2022]
Abstract
The gamma-aminobutyric acid A (GABA-A) receptor mediates inhibitory neurotransmission in the brain and as such may be involved in certain neurological movement disorders, such as tremor. GABA-A receptor alpha 1 (Gabra)(-/-) mice have been reported to exhibit postural and kinetic, alcohol-responsive, tremor that is characteristic of essential tremor (ET), the most common form of tremor. To determine whether ET is associated with the GABRA1 gene mutation, we screened 76 patients with familial ET and found a novel nucleotide variant: IVS8+24 G>T (nt 6119289) in a male patient, and a known 156T>C polymorphism (nt 6090903) in exon 4 in 41% patients, which results in a silent mutation (G52G). No significant association between 156T>C variant and disease risk was found (adjusted OR=0.95, 95% CI=0.57-1.61; p=0.858) by further analysis of 121 familial ET patients and 114 normal controls, except a novel 96A>G (Q32Q; nt 6090743) variant, found in a normal control. Since the 156T>C variant appears to be not pathogenically relevant, our results suggest that missense, nonsense or splice site mutation in the coding region of the GABRA1 gene is not a major genetic cause of ET in Caucasian subjects.
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Affiliation(s)
- Hao Deng
- Department of Neurology, Baylor College of Medicine, 6501 Fannin Street, Houston, TX 77030, USA
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14
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Abstract
BACKGROUND AND PURPOSE Although essential tremor (ET) is one of the most common movement disorders, its pathogenesis remains obscure. The ventral intermediate nucleus of the thalamus (VIM nucleus) is suggested to play an important role in the occurrence of disease. In this study, the authors investigated the presence of biochemical or metabolic alterations in the thalamus of patients with ET using magnetic resonance (MR) spectroscopy. METHODS The study group included 14 patients with ET who suffered from tremor predominantly in their right arm and 9 healthy controls. All patients and controls were right handed. Following conventional cranial MR imaging, single voxel proton MR spectroscopy of the thalamus involving the VIM nuclei was performed bilaterally in both the patients with ET and controls. Metabolite peaks of choline (Cho), creatine (Cr), and Nacetylaspartate (NAA) were obtained from each spectroscopic volume of interest. The right and left thalamic NAA/Cr and Cho/ Cr ratios were compared first within the patient group and then between the control and patient groups. The differences in age and spectroscopic data between groups were assessed using the Mann-Whitney U test, whereas the comparison within groups between left thalamus and right thalamus was done by the Wilcoxon test. RESULTS In patients with ET, the NAA/Cr ratio of the right thalamus was found to be significantly higher than the NAA/Cr ratio of the left thalamus (P= .02). However, NAA/Cr and Cho/Cr ratios were found to be similar (P> .05) when we compared the control and patient groups for the right thalamus and then the left thalamus. CONCLUSION These data present preliminary evidence for metabolic alterations of the contralateral thalamus (namely, low NAA/Cr ratio) in ET patients with predominantly involved right arm. However, the series is small and further data are necessary to clear the subject adequately.
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15
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Bhidayasiri R. How useful is (123I) beta-CIT SPECT in the diagnosis of Parkinson's disease? Rev Neurol Dis 2006; 3:19-22. [PMID: 16596082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Because clinical features of parkinsonism can occur in other forms of parkinsonian syndromes in addition to Parkinson's disease, neuroimaging may have a role in determining true disease status. Iodine-123 ((123)I) (2beta-carboxymethoxy-3beta-[4-iodophenyl] tropane) or ((123)I) beta-CIT is a recently developed diagnostic biomarker of Parkinson's disease that provides in vivo information about nigrostriatal degeneration. In clinical trials, beta-CIT single photon emission computed tomography (SPECT) has been shown to be a highly sensitive diagnostic tool in differentiating clinically probable Parkinson's disease from normal subjects and essential tremor patients. As a tool for differentiating Parkinson's disease from atypical parkinsonian syndromes, ((123)I) beta-CIT SPECT may have more limited use because of more extensive postsynaptic pathology in the latter. Differentiating among various parkinsonian syndromes may be improved by methodological refinements, a combined strategy of imaging presynaptic and postsynaptic sites, or by metabolic imaging.
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Affiliation(s)
- Roongroj Bhidayasiri
- Department of Neurology, UCLA Medical Center, The David Geffen UCLA School of Medicine, Los Angeles, CA, USA
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16
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Abstract
BACKGROUND About 20% of patients with familial hemiplegic migraine (FHM) develop progressive cerebellar signs. Genetic studies have established an association with mutations in the CACNA1A gene. However, the mechanisms underlying cerebellar involvement are largely unknown. OBJECTIVE To use proton MR spectroscopy (1H-MRS) to investigate metabolic alterations in the cerebellum as well as cortical regions known to be involved in the propagation of migraine aura. METHODS Fifteen CACNA1A mutation carriers from three FHM families and 17 healthy control subjects were studied. Eleven patients had clinical signs of cerebellar involvement. LCModel fits were used to estimate absolute concentrations of N-acetyl aspartate (NAA), myo-inositol (mI), glutamate (Glu), choline-containing compounds, total creatine, and lactate in the superior cerebellar vermis (SCV), parietal cortex, and occipital cortex. To control for atrophy effects, automated image segmentation was performed using SPM99. The brain parenchyma fraction (BPF) was determined for all three regions. RESULTS Compared with controls, the brain parenchyma fraction (BPF), NAA, and Glu were significantly reduced and mI was significantly elevated in the SCV of patients with FHM. In contrast, no metabolite alterations were found in supratentorial regions. BPF and NAA in the SCV significantly correlated with cerebellar scores, in particular, gait ataxia. CONCLUSIONS The findings suggest that there is a regionally distinct neuronal impairment in the superior cerebellar vermis that exceeds macroscopic tissue loss. Correlations with clinical scores emphasize the functional relevance of localized atrophy (brain parenchyma fraction) and N-acetyl aspartate levels. These measures may be useful to monitor disease progression. The observed reduction in glutamate may in part reflect impaired glutamatergic neurotransmission.
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Affiliation(s)
- M Dichgans
- Department of Neurology, Klinikum Grosshadern, Ludwig Maximilians University, Munich, Germany.
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17
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Breit S, Reimold M, Reischl G, Klockgether T, Wüllner U. [(11)C]d-threo-methylphenidate PET in patients with Parkinson's disease and essential tremor. J Neural Transm (Vienna) 2005; 113:187-93. [PMID: 15959851 DOI: 10.1007/s00702-005-0311-7] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2004] [Accepted: 03/25/2005] [Indexed: 11/26/2022]
Abstract
Twenty Parkinson's disease (PD) patients, 6 patients with essential tremor and 10 healthy controls were studied with the dopamine transporter ligand [(11)C]d-threo-methylphenidate ([(11)C]dMP) and positron emission tomography (PET) to assess dopamine terminal loss in relation to disease duration and motor disability. Dopamine transporter availability was expressed as [(11)C]dMP binding potential (BP(dMP)) in percentage of the mean of healthy controls. In PD patients (age at onset 57.7 +/- 8.9 yrs; disease duration 5.2 +/- 3.3 yrs; UPDRS motor score 24.2 +/- 9.8; Hoehn & Yahr 2.1 +/- 0.8; mean +/- SD) BP(dMP) was reduced to 30% (range: 11-55%) in the putamen and 52% (range: 14-96%) in the caudate nucleus. BP(dMP) in the putamen closely correlated with the UPDRS motor score (r = -0.79, p < 0.001), and disease duration (r = -0.76, p < 0.001) but not with age at onset. The correlation with the UPDRS score depended on akinesia and rigidity, while the tremor scores were related neither to putamen nor caudate BP(dMP). Interestingly, when plotted over disease duration, PD patients with severe asymmetry of symptoms showed significantly lower BP(dMP) in the contralateral putamen (exponential fit: 34% at onset) than the other PD patients (41% at onset), indicating a different symptomatic threshold of these subgroups and an even closer correlation with the hypothetical "true" disease duration. The exponential fit across all patients indicated a mean symptomatic threshold of 37% contra- and 62% ipsilateral, corresponding with an observed mean BP(dMP) of 51% (average contra- and ipsilateral) in those patients with disease duration less than one year. No differences in BP(dMP) were observed between patients with essential tremor and healthy controls. [(11)C]dMP appears to be a useful and sensitive marker of dopaminergic dysfunction in PD and can be used to assess and monitor disease severity.
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Affiliation(s)
- S Breit
- Department of Neurology, University of Tübingen, Tübingen, Germany.
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18
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Kralic JE, Criswell HE, Osterman JL, O'Buckley TK, Wilkie ME, Matthews DB, Hamre K, Breese GR, Homanics GE, Morrow AL. Genetic essential tremor in gamma-aminobutyric acidA receptor alpha1 subunit knockout mice. J Clin Invest 2005; 115:774-9. [PMID: 15765150 PMCID: PMC1052003 DOI: 10.1172/jci23625] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2004] [Accepted: 12/21/2004] [Indexed: 12/16/2022] Open
Abstract
Essential tremor is the most common movement disorder and has an unknown etiology. Here we report that gamma-aminobutyric acidA (GABA(A)) receptor alpha1-/- mice exhibit postural and kinetic tremor and motor incoordination that is characteristic of essential tremor disease. We tested mice with essential-like tremor using current drug therapies that alleviate symptoms in essential tremor patients (primidone, propranolol, and gabapentin) and several candidates hypothesized to reduce tremor, including ethanol; the noncompetitive N-methyl-D-aspartate receptor antagonist MK-801; the adenosine A1 receptor agonist 2-chloro-N6-cyclopentyladenosine (CCPA); the GABA(A) receptor modulators diazepam, allopregnanolone, and Ro15-4513; and the L-type Ca2+ channel antagonist nitrendipine. Primidone, propranolol, and gabapentin reduced the amplitude (power) of the pathologic tremor. Nonsedative doses of ethanol eliminated tremor in mice. Diazepam, allopregnanolone, Ro15-4513, and nitrendipine had no effect or enhanced tremor, whereas MK-801 and CCPA reduced tremor. To understand the etiology of tremor in these mice, we studied the electrophysiological properties of cerebellar Purkinje cells. Cerebellar Purkinje cells in GABA(A) receptor alpha1-/- mice exhibited a profound loss of all responses to synaptic or exogenous GABA, but no differences in abundance, gross morphology, or spontaneous synaptic activity were observed. This genetic animal model elucidates a mechanism of GABAergic dysfunction in the major motor pathway and potential targets for pharmacotherapy of essential tremor.
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Affiliation(s)
- Jason E Kralic
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-7178, USA
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19
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Louis ED, Shungu DC, Mao X, Chan S, Jurewicz EC. Cerebellar metabolic symmetry in essential tremor studied with1H magnetic resonance spectroscopic imaging: Implications for disease pathology. Mov Disord 2004; 19:672-7. [PMID: 15197706 DOI: 10.1002/mds.20019] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
The pathological basis for essential tremor (ET) is not known; however, metabolic changes in the cerebellum can be observed in positron emission tomography (PET) and (1)H magnetic resonance spectroscopic imaging (MRSI) studies. Tremor is relatively symmetric in ET, suggesting that underlying metabolic changes could be also symmetric. The degree of metabolic asymmetry in the cerebellum, however, has not yet been studied in ET, and knowledge about distribution and laterality of metabolic changes might shed some light on basic disease mechanisms. We measured brain metabolism (N-acetylaspartate[NAA]/creatine [tCR]) to obtain an asymmetry index for cerebellar cortical metabolism ET patients compared with that in controls. This index, a percentage, was calculated as [absolute value (value right - value left)]/(value right + value left) x 100. Multislice (1)H MRSI data were acquired for 20 patients and 11 controls. In ET patients, mean right and left cerebellar cortical NAA/tCR values were 1.61 +/- 0.42 and 1.55 +/- 0.38, respectively, compared with 1.81 +/- 0.62 and 1.87 +/- 0.49 in controls. The difference between right and left cerebellar cortical NAA/tCR was also calculated for each subject. In ET patients, the mean right-left difference was 0.14 +/- 0.11, compared with 0.32 +/- 0.27 in controls (P = 0.016). The mean cerebellar cortical asymmetry index was low in ET (8.8 +/- 6.1%), one-half of that in controls (17.0 +/- 13.7%, P = 0.027). These data suggest that pathological lesions in ET patients, which remain elusive, might be distributed similarly in each cerebellar cortex. Postmortem studies are needed to confirm these preliminary imaging results.
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Affiliation(s)
- Elan D Louis
- Gertrude H. Sergievsky Center, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA.
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20
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Abstract
Functional imaging of the dopamine transporter (DAT) defines integrity of the dopaminergic system and has its main clinical application in patients with mild, incomplete, or uncertain parkinsonism. Imaging with specific single positron emission computerised tomography ligands for DAT (FP-CIT, beta-CIT, IPT, TRODAT) provides a marker for presynaptic neuronal degeneration. Striatal uptake correlates with disease severity, in particular bradykinesia and rigidity, and monitoring of progression assists in clinical trials of potential neuroprotective drugs. DAT imaging is abnormal in idiopathic Parkinson's disease, multiple system atrophy and progressive supranuclear palsy and does not distinguish between these disorders. Dopamine loss is seen even in the earliest clinical presentations of true parkinsonism; a normal scan suggests an alternative diagnosis such as essential tremor, vascular parkinsonism (unless there is focal basal ganglia infarction), drug-induced parkinsonism, or psychogenic parkinsonism. Congruence between working clinical diagnosis and DAT imaging increases over time in favour of baseline DAT imaging results. Additional applications are characterising dementia with parkinsonian features (abnormal results in dementia with Lewy bodies, normal in Alzheimer's disease); and differentiating juvenile-onset Parkinson's disease (abnormal DAT) from dopa-responsive dystonia (normal DAT).
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Affiliation(s)
- Vicky Marshall
- Institute of Neurological Sciences, Glasgow, United Kingdom.
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21
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Abstract
PET imaging provides the means to study neurochemical, hemodynamic, or metabolic processes that underlie movement disorders in vivo. Because the extent of presynaptic nigrostriatal dopaminergic denervation can be quantified in PD even at an early or preclinical stage of the disease, PET imaging may allow the selection of at-risk subjects for neuroprotective intervention trials. These techniques may also provide markers to follow progression of disease or evaluate the effects of neurorestorative interventions in patients who have more advanced disease. PET is expected to play an increasing role in the selection of patients who have PD for deep brain stimulation. Dopaminergic studies may have a limited clinical role in the diagnosis of patients who have symptoms that suggestive of PD yet do not respond to typical dopaminergic drugs, such as patients who have vascular parkinsonism or ET with mild resting tremor who may have normal dopaminergic innervation. The differential diagnosis between PD and multiple system atrophy, progressive supranuclear palsy, or corticobasal degeneration is not yet clearly established by PET, but combined pre- and postsynaptic dopaminergic imaging may be able to distinguish early idiopathic PD from atypical parkinsonian disorders, in general. Huntington's chorea is characterized by more prominent striatal dopamine receptor loss, whereas nigrostriatal denervation is present to a lesser degree. Patients who have TS may have enhanced synaptic dopamine release in the putamen. Functional imaging studies have generally failed to demonstrate nigrostriatal denervation in essential tremor or idiopathic dystonia. Studies have shown striatal dopamine receptor loss in selected subtypes of dystonic patients. In conclusion, it is expected that PET will help us to better understand the pathophysiology of movement disorders, increase the diagnostic accuracy, allow preclinical diagnosis, monitor disease progression, and evaluate the efficacy of therapeutic agents. Pharmacologic radioligand displacement studies and the development of new nondopaminergic ligands may further aid in the unraveling of cerebral mechanisms that underlie movement disorders.
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Affiliation(s)
- Nicolaas I Bohnen
- Department of Neurology and Radiology, University of Pittsburgh School of Medicine, 3471 Fifth Avenue, Suite 811, Pittsburgh, PA 15213, USA.
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Kanyó B, Argyelán M, Dibó G, Szakonyi Z, Vécsei L, Fülöp F, Láncz A, Forgács P, Pávics L. [Imaging of dopamine transporter with Tc99m-Trodat-SPECT in movement disorders]. Ideggyogy Sz 2003; 56:231-40. [PMID: 12971118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
Abstract
UNLABELLED 99mTc-TRODAT-1 is a new, technetium based radiopharmaceutical that selectively binds to the dopamine transporters. The aim of the study was to evaluate the dopamine transporter status in movement disorders. METHODS In eight healthy volunteers (age range 22-58 years), 28 patients with Parkinson's disease (age range 42-80 years), 10 patients with Parkinsonian syndrome (age range 51-79 years) and 13 patients with essential tremor (age range 43-71 years) were 99mTc-TRODAT-SPECT tests performed. The results were evaluated visually and semiquantitatively. RESULTS The visual assessments were concordant with those of the semiquantitative in each case. The 99mTc-TRODAT uptake of the striatum was referenced to the cerebellum, the frontal and occipital cortex. The best deviation was found in aspect of the occipital cortex. The striatum/occipital ratio was the following: healthy volunteers: 2.12 +/- 0.27; Parkinson's disease: 1.52 +/- 0.27; Parkinsonian syndrome: 1.57 +/- 0.26; essential tremor: 2.06 +/- 0.69. The striatal dopamine transporter availability was significantly lower in subjects with Parkinson's disease or Parkinsonian syndrome compared to the control subjects. There was no difference between healthy volunteers and patients with essential tremor. Using discriminant analysis, the discriminant function had significantly different values in the group of Parkinson's disease than in Parkinsonian syndrome: f = -3.675 x caud/occipit + 6.293 x put/occipit -2.548. CONCLUSION 99mTc-TRODAT-SPECT is able to visualise the presynaptic dopaminergic degeneration. This method itself can be useful in differential diagnosis in some type of movement disorders.
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Affiliation(s)
- Balázs Kanyó
- Szegedi Tudományegyetem, Nukleáris Medicina Intézet, H-6720 Szeged, Korányi fasor 8.
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Benamer HTS, Oertel WH, Patterson J, Hadley DM, Pogarell O, Höffken H, Gerstner A, Grosset DG. Prospective study of presynaptic dopaminergic imaging in patients with mild parkinsonism and tremor disorders: Part 1. Baseline and 3-month observations. Mov Disord 2003; 18:977-84. [PMID: 14502664 DOI: 10.1002/mds.10482] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To record prospectively, from early presentation, the clinical features of parkinsonism and tremor disorders, in relation to evidence of dopaminergic deficit shown with [(123)I]-FP-CIT (DaTSCAN, Amersham Health) single photon emission computerised tomography (SPECT). Clinical signs were recorded in 62 patients, of whom 24 failed standard Parkinson's disease (PD) and essential tremor criteria, and 38 fulfilled UK Brain Bank step 1 PD criteria. Striatal radioligand uptake was graded visually as normal or abnormal, and specific:nonspecific ratios were calculated. Bradykinesia and rigidity showed significant overall association with abnormal scans (P < or = 0.003), but rest tremor did not (P = NS). In the 24 patients not fulfilling specific criteria (mean age 63 [SD 9] years, disease duration 3 [SD 4] years), 10 (42%) had abnormal visual SPECT assessment and 14 (58%) had normal scans. Of 38 patients with early PD by clinical criteria (mean age 60 [SD 9] years, disease duration 3 [SD 1.7] years), 33 (87%) were visually abnormal. Baseline clinical diagnosis corresponded with SPECT imaging results in 51 of 62 cases (82%), which increased to 56 of 62 cases (90%) with amendment of seven clinical diagnoses at 3 months (blind to SPECT results). Akinetic-rigid cardinal diagnostic features of parkinsonism associate well with dopaminergic deficit in patients with early and mild clinical features. When these clinical features are uncertain, or the patient fails clinical diagnostic criteria, testing for dopaminergic deficit with [(123)I]-FP-CIT SPECT may assist the diagnostic process.
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Affiliation(s)
- Hani T S Benamer
- Neurology Department, New Cross Hospital, Wolverhampton, United Kingdom.
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Løkkegaard A, Werdelin LM, Friberg L. Clinical impact of diagnostic SPET investigations with a dopamine re-uptake ligand. Eur J Nucl Med Mol Imaging 2002; 29:1623-9. [PMID: 12458397 DOI: 10.1007/s00259-002-0938-7] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2002] [Accepted: 06/27/2002] [Indexed: 12/01/2022]
Abstract
The diagnosis of Parkinson's disease is based on clinical features with pathological verification. However, autopsy has been found to confirm a specialist diagnosis in only about 75% of cases. Especially early in the course of the disease, the clinical diagnosis can be difficult. Imaging of presynaptic dopamine transporters (DAT receptors) has provided a possible diagnostic probe in the evaluation of Parkinson's disease. The cocaine analogue [(123)I]-2-beta-carboxymethoxy-3-beta(4-iodophenyl)tropane ([(123)I]-beta-CIT) is one of several radioligands that have been developed for single-photon emission tomography (SPET). The purpose of this study was to evaluate the impact of [(123)I]-beta-CIT SPET on the diagnosis and clinical management of patients with a primary, tentative diagnosis of parkinsonism. We undertook a retrospective evaluation of the clinical records of 90 consecutive patients referred to [(123)I]-beta-CIT SPET from the neurological department, Bispebjerg Hospital. In 58 subjects the scans revealed altered tracer uptake consistent with Parkinson's disease, progressive supranuclear palsy and multiple system atrophy. A significant change in the management or treatment because of the scan was found in 25 patients (28%). The sensitivity of the examination was 97% and the specificity 83%. In conclusion, a significant clinical impact of DAT receptor SPET imaging was found. DAT receptor imaging is a useful diagnostic probe in patients with a possible diagnosis of parkinsonism.
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Affiliation(s)
- Annemette Løkkegaard
- Department of Neurology, Bispebjerg Hospital, Bispebjerg Bakke 23, 2400 Copenhagen NV, Denmark.
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Louis ED, Shungu DC, Chan S, Mao X, Jurewicz EC, Watner D. Metabolic abnormality in the cerebellum in patients with essential tremor: a proton magnetic resonance spectroscopic imaging study. Neurosci Lett 2002; 333:17-20. [PMID: 12401550 DOI: 10.1016/s0304-3940(02)00966-7] [Citation(s) in RCA: 137] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The pathological basis for essential tremor (ET) is unknown. We used proton magnetic resonance spectroscopic imaging (1H MRSI) in 16 ET patients and 11 controls to measure levels of intracellular metabolites, including N-acetyl-L-aspartate (NAA) and total choline, relative to total creatine (tCR), in several brain regions (cerebellum, thalamus, basal ganglia). Multislice 1H MRSI data were acquired on a 1.5 T GE Signa Scanner by prescribing four 15-mm axial-oblique slices. The mean (standard deviation) cerebellar cortical NAA/tCR was reduced in cases compared to controls (1.53 [0.36] versus 1.91 [0.49], P = 0.03). There was an inverse association between cerebellar cortical NAA/tCR and dominant arm tremor severity (r = -0.59, P = 0.02). The reduction in cerebellar cortical NAA/tCR indicates that there is neuronal damage or loss in ET, suggesting that ET may be a neurodegenerative disease.
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Affiliation(s)
- Elan D Louis
- Gertrude H Sergievsky Center, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.
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Abstract
BACKGROUND The pathogenesis of essential tremor (ET) is unknown, but it could be neurodegenerative. Weight loss has been observed in patients with neurodegenerative diseases. OBJECTIVES To compare body mass index (BMI) (calculated as weight in kilograms divided by the square of height in meters) in ET cases and controls and to determine whether BMI is correlated with tremor severity and duration. METHODS Patients with ET were ascertained from the Neurological Institute of New York, New York, NY. Control subjects were recruited from 2 studies at the same institution. Height and weight were measured and BMI was calculated. Dietary data were collected using a Willett Semi-Quantitative Food-Frequency Questionnaire. Tremor severity was assessed using a clinical scale and the Klove Matthews Motor Steadiness Battery. RESULTS The 78 cases and 242 controls were of similar age. Mean (SD) BMI in cases vs controls was 26.5 (5.0) vs 28.2 (4.8) (P =.008). This difference remained significant in an unconditional linear regression analysis that adjusted for age, sex, ethnicity, and years of education (P =.02). Mean daily caloric intake was similar in cases and controls. In cases, BMI was negatively correlated with both measures of tremor severity (r = -0.22; P =.05 and r = -0.24; P =.03) and with tremor duration (r = -0.22; P =.05). CONCLUSIONS The BMI was lower in ET cases than in controls, and lower BMI was associated with disease of greater severity and longer duration. Caloric intake did not differ between groups, suggesting that lower BMI is not due to a reduction in calories. Lower BMI may be due to increased energy expenditure in ET.
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Affiliation(s)
- Elan D Louis
- Unit 198, Neurological Institute, College of Physicians and Surgeons, Columbia University, 710 W 168th St, New York, NY 10032.
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Abstract
Recent experimental and clinical studies clearly suggest the role of gamma-aminobutyric acid (GABA) in the pathogenesis of tremors. The present study was undertaken to investigate the effect of baclofen, a GABA B receptor agonist on harmaline induced tremors. Four groups of female Wistar rats weighing 100+/-15 g were injected with harmaline (10 mg/kg, intraperitoneally) for inducing experimental tremors. The animals in groups 2, 3 and 4 were given baclofen by gavage at doses of 2.5, 5 and 10 mg/kg, respectively, half an hour before harmaline administration, whereas, the rats in group 1 served as control and received water. The latency of onset, intensity and duration of tremor and electromyographic (EMG) responses were recorded. Treatment with baclofen resulted in a dose dependent decrease in the intensity of tremor. Our EMG study also revealed a significant decrease in the amplitude of tremors in baclofen treated rats. A highly significant increase in latency of onset of tremor was observed in the rats treated with high dose (10 mg/kg) of baclofen only. This study clearly suggests beneficial effects of baclofen in harmaline induced tremors.
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Affiliation(s)
- M Tariq
- Research Center, Armed Forces Hospital, P.O. Box 7897 (W-912), Riyadh 11159, Saudi Arabia
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Pigullo S, Di Maria E, Marchese R, Assini A, Bellone E, Scaglione C, Vitale C, Bonuccelli U, Barone P, Ajmar F, Martinelli P, Abbruzzese G, Mandich P. No evidence of association between CAG expansions and essential tremor in a large cohort of Italian patients. J Neural Transm (Vienna) 2001; 108:297-304. [PMID: 11341481 DOI: 10.1007/s007020170075] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Essential tremor (ET) is one of the most common movement disorders. However the pathogenesis is as yet unknown, although a genetic cause has long been recognised. Clinical and molecular evidences suggested that the ET gene might contain a CAG expanded region. In a cohort of Italian ET patients Repeat Expansion Detection (RED) approach did not demonstrate large CAG expansions. We extended the study towards specific targets: the channel proteins hSKCa3 and CACNL1A4. Direct assessment of CAG stretches within these two genes did not demonstrate any CAG expansion in affected subjects. Also a case-control analysis failed to reveal any evidence of association, thus excluding these genes as a cause of ET.
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Affiliation(s)
- S Pigullo
- Department of Oncology, Biology and Genetics, University of Genova, Italy
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