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Lai YY, Hsieh KC, Chew KT, Nguyen D, Siegel JM. Striatal mechanism of the restless legs syndrome. Sleep 2022; 45:6583453. [PMID: 35537196 PMCID: PMC9272194 DOI: 10.1093/sleep/zsac110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 04/28/2022] [Indexed: 11/14/2022] Open
Abstract
Abstract
Study Objectives
Brain iron deficiency has been reported to be associated with the restless legs syndrome (RLS). However, 30%–50% of RLS patients do not respond to iron therapy, indicating that mechanisms other than brain iron deficiency may also participate in this disease. The striatum is known to be involved in the modulation of motor activity. We speculated that dysfunction of the striatum may induce RLS.
Methods
Two groups, wild-type (WT) and iron-deficient (ID) rats were used. Each group was divided into two subgroups, control and N-methyl-d-aspartate striatal-lesioned. After baseline recording, striatal-lesioned wild-type (WT-STL) and striatal-lesioned iron-deficient (ID-STL) rats were given pramipexole and thioperamide injections. Iron-deficient and ID-STL rats were then given a standard rodent diet for 4 weeks, and their sleep and motor activity were recorded.
Results
WT-STL rats showed periodic leg movements (PLM) in wake, an increase in PLM in slow wave sleep (SWS), a decrease in rapid-eye-movement sleep, and a decrease in the daily average duration of episodes in SWS. The sleep–wake pattern and motor activity did not differ between ID and ID-STL rats. Thioperamide or pramipexole injection decreased PLM in sleep and in wake in WT-STL rats and ID-STL rats. Unlike ID rats, whose motor hyperactivity can be reversed by iron replacement, PLM in wake and in sleep in ID-STL rats were not fully corrected by iron treatment.
Conclusions
Lesions of the striatum generate RLS-like activity in rats. Dysfunction of the striatum may be responsible for failure to respond to iron treatment in some human RLS patients.
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Affiliation(s)
- Yuan-Yang Lai
- Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine, University of California , Los Angeles, CA , USA
- VA Greater Los Angeles HealthCare System , Sepulveda, 16111 Plummer Street, North Hills, CA , USA
- Greater Los Angeles Veterans Research and Education Foundation , 11301 Wilshire Blvd, Los Angeles, CA , USA
| | - Kung-Chiao Hsieh
- VA Greater Los Angeles HealthCare System , Sepulveda, 16111 Plummer Street, North Hills, CA , USA
| | - Keng-Tee Chew
- VA Greater Los Angeles HealthCare System , Sepulveda, 16111 Plummer Street, North Hills, CA , USA
| | - Darian Nguyen
- Greater Los Angeles Veterans Research and Education Foundation , 11301 Wilshire Blvd, Los Angeles, CA , USA
| | - Jerome M Siegel
- Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine, University of California , Los Angeles, CA , USA
- VA Greater Los Angeles HealthCare System , Sepulveda, 16111 Plummer Street, North Hills, CA , USA
- Brain Research Institute, University of California, Los Angeles , CA , USA
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Khachatryan SG, Ferri R, Fulda S, Garcia-Borreguero D, Manconi M, Muntean ML, Stefani A. Restless legs syndrome: Over 50 years of European contribution. J Sleep Res 2022; 31:e13632. [PMID: 35808955 PMCID: PMC9542244 DOI: 10.1111/jsr.13632] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 04/21/2022] [Accepted: 04/22/2022] [Indexed: 11/28/2022]
Abstract
Restless legs syndrome (RLS) is a sensorimotor neurological disorder characterised by an urge to move the limbs with a circadian pattern (occurring in the evening/at night), more prominent at rest, and relieved with movements. RLS is one of the most prevalent sleep disorders, occurring in 5%-10% of the European population. Thomas Willis first described RLS clinical cases already in the 17th century, and Karl-Axel Ekbom described the disease as a modern clinical entity in the 20th century. Despite variable severity, RLS can markedly affect sleep (partly through the presence of periodic leg movements) and quality of life, with a relevant socio-economic impact. Thus, its recognition and treatment are essential. However, screening methods present limitations and should be improved. Moreover, available RLS treatment options albeit providing sustained relief to many patients are limited in number. Additionally, the development of augmentation with dopamine agonists represents a major treatment problem. A better understanding of RLS pathomechanisms can bring to light novel treatment possibilities. With emerging new avenues of research in pharmacology, imaging, genetics, and animal models of RLS, this is an interesting and constantly growing field of research. This review will update the reader on the current state of RLS clinical practice and research, with a special focus on the contribution of European researchers.
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Affiliation(s)
- Samson G Khachatryan
- Department of Neurology and Neurosurgery, National Institute of Health, Yerevan, Armenia.,Sleep Disorders Center, Somnus Neurology Clinic, Yerevan, Armenia
| | | | - Stephany Fulda
- Sleep Medicine Unit, Neurocenter of Southern Switzerland, Ospedale Civico, Lugano, Switzerland
| | | | - Mauro Manconi
- Sleep Medicine Unit, Neurocenter of Southern Switzerland, Ospedale Civico, Lugano, Switzerland.,Department of Neurology, University Hospital, Inselspital, Bern, Switzerland
| | - Maria-Lucia Muntean
- Center for Parkinson's Disease and Movement Disorders, Paracelsus-Elena Klinik, Kassel, Germany
| | - Ambra Stefani
- Sleep Disorders Clinic, Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
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Lai YY, Kodama T, Hsieh KC, Nguyen D, Siegel JM. Substantia nigra pars reticulata-mediated sleep and motor activity regulation. Sleep 2021; 44:5893883. [PMID: 32808987 DOI: 10.1093/sleep/zsaa151] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 08/01/2020] [Indexed: 12/20/2022] Open
Abstract
STUDY OBJECTIVES The substantia nigra pars reticulata (SNR) is a major output nucleus of the basal ganglia. Animal studies have shown that lesions of the SNR cause hyposomnia and motor hyperactivity, indicating that the SNR may play a role in the control of sleep and motor activity. METHODS Eight 8- to 10-week-old adult male Sprague-Dawley rats were used. After 3 days of baseline polysomnographic recording, dialysates were collected from the lateral SNR across natural sleep-wake states. Muscimol and bicuculline were microinfused into the lateral SNR. RESULTS We found that GABA release in the lateral SNR is negatively correlated with slow wave sleep (SWS; R = -0.266, p < 0.01, n = 240) and positively correlated with waking (R = 0.265, p < 0.01, n = 240) in rats. Microinfusion of muscimol into the lateral SNR decreased sleep time and sleep quality, as well as eliciting motor hyperactivity in wake and increased periodic leg movement in SWS, while bicuculline infused into the lateral SNR increased sleep and decreased motor activity in SWS in rats. Muscimol infusion skewed the distribution of inter-movement intervals, with most between 10 and 20 s, while a flat distribution of intervals between 10 and 90 s was seen in baseline conditions. CONCLUSIONS Activation of the lateral SNR is important for inducing sleep and inhibiting motor activity prior to and during sleep, and thus to the maintenance of sleep. Abnormal function of the lateral SNR may cause hyposomnia and motor hyperactivity in quiet wake and in sleep.
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Affiliation(s)
- Yuan-Yang Lai
- Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, CA.,VA Greater Los Angeles HealthCare System, North Hills, CA.,Greater Los Angeles Veterans Research and Education Foundation, Los Angeles, CA
| | - Tohru Kodama
- Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, CA.,Physiological Psychology Lab, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Kung-Chiao Hsieh
- VA Greater Los Angeles HealthCare System, North Hills, CA.,Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA
| | - Darian Nguyen
- Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, CA
| | - Jerome M Siegel
- Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, CA.,VA Greater Los Angeles HealthCare System, North Hills, CA
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Lai YY, Hsieh KC, Cheng YH, Chew KT, Nguyen D, Ramanathan L, Siegel JM. Striatal histamine mechanism in the pathogenesis of restless legs syndrome. Sleep 2020; 43:5610750. [PMID: 31671173 PMCID: PMC8491621 DOI: 10.1093/sleep/zsz223] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 03/07/2019] [Indexed: 11/13/2022] Open
Abstract
STUDY OBJECTIVES Restless legs syndrome (RLS) has been hypothesized to be generated by abnormal striatal dopamine transmission. Dopaminergic drugs are effective for the treatment of RLS. However, long-term use of dopaminergic drugs causes adverse effects. We used iron-deficient (ID) and iron-replacement (IR) rats to address the neuropathology of RLS and to determine if a histamine H3 receptor (H3R) antagonist might be a useful treatment. Histamine H3R antagonists have been shown to decrease motor activity. METHODS Control and ID rats were surgically implanted with electrodes for polysomnographic recording. After 3 days of baseline polysomnographic recordings, rats were systemically injected with the H3R agonist, α-methylhistamine, and antagonist, thioperamide. Recordings were continued after drug injection. Striatal H3R levels from control, ID, and IR rats were determined by western blots. Blood from control, ID, and IR rats was collected for the measurement of hematocrit levels. RESULTS α-Methylhistamine and thioperamide increased and decreased motor activity, respectively, in control rats. In ID rats, α-methylhistamine had no effect on motor activity, whereas thioperamide decreased periodic leg movement (PLM) in sleep. Sleep-wake states were not significantly altered under any conditions. Striatal H3R levels were highest in ID rats, moderate to low in IR rats, and lowest in control rats. Striatal H3R levels were also found to positively and negatively correlate with PLM in sleep and hematocrit levels, respectively. CONCLUSIONS A striatal histamine mechanism may be involved in ID anemia-induced RLS. Histamine H3R antagonists may be useful for the treatment of RLS.
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Affiliation(s)
- Yuan-Yang Lai
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, CA
| | - Kung-Chiao Hsieh
- Veterans Administration Greater Los Angeles HealthCare System (VAGLAHS), Sepulveda, Los Angeles, CA
| | - Yu-Hsuan Cheng
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, CA
| | - Keng-Tee Chew
- Veterans Administration Greater Los Angeles HealthCare System (VAGLAHS), Sepulveda, Los Angeles, CA
| | - Darian Nguyen
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, CA
| | - Lalini Ramanathan
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, CA
| | - Jerome M Siegel
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, CA.,Veterans Administration Greater Los Angeles HealthCare System (VAGLAHS), Sepulveda, Los Angeles, CA
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Lo Martire V, Alvente S, Bastianini S, Berteotti C, Valli A, Manconi M, Zoccoli G, Silvani A. Sleep and Tibialis Anterior Muscle Activity in Mice With Mild Hypoxia and Iron Deficiency: Implications for the Restless Legs Syndrome. Front Physiol 2018; 9:1818. [PMID: 30618828 PMCID: PMC6304696 DOI: 10.3389/fphys.2018.01818] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 12/05/2018] [Indexed: 12/14/2022] Open
Abstract
Restless legs syndrome (RLS) is a neurological disorder that entails an urge to move with a circadian pattern during the evening/night. RLS may be accompanied by decreased sleep time and increased occurrence of periodic leg movements during sleep (PLMS), which involve bursts of tibialis anterior (TA) muscle electromyogram (EMG). Mild hypoxia and non-anemic iron deficiency, a highly prevalent nutritional deficiency, are relatively unexplored factors in RLS pathophysiology. We tested whether mice exposed to mild hypoxia, alone or in combination with non-anemic iron deficiency, show decreased sleep time particularly in the light (rest) period and increased occurrence of TA EMG phasic events similar to human PLMS. Female C57BL/6J mice were fed diets with low or normal iron for 6 months from weaning and instrumented with electrodes to record the electroencephalogram and the EMG of both TA muscles. Mice were recorded in a whole-body plethysmograph while breathing a normoxic or mildly hypoxic (15% O2) gas mixture for 48 h. Hypoxia increased minute ventilation during sleep. The low-iron diet decreased liver and serum iron, leaving blood hemoglobin and brainstem iron levels unaffected. Hypoxia, either alone or in combination with non-anemic iron deficiency, decreased non-rapid-eye-movement (non-REM) sleep time, but this occurred irrespective of the light/dark period and was not associated with increased occurrence of TA EMG events during non-REM sleep. These results do not support the hypothesis that mild hypoxia is sufficient to cause signs of RLS, either alone or in combination with non-anemic iron deficiency, pointing to the necessity of further susceptibility factors.
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Affiliation(s)
- Viviana Lo Martire
- Laboratory of Physiological Regulations in Sleeping Mice, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Sara Alvente
- Laboratory of Physiological Regulations in Sleeping Mice, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Stefano Bastianini
- Laboratory of Physiological Regulations in Sleeping Mice, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Chiara Berteotti
- Laboratory of Physiological Regulations in Sleeping Mice, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Alice Valli
- Laboratory of Physiological Regulations in Sleeping Mice, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Mauro Manconi
- Sleep and Epilepsy Center, Neurocenter of Southern Switzerland, Civic Hospital (EOC) of Lugano, Lugano, Switzerland.,Department of Neurology, Bern University Hospital, Bern, Switzerland
| | - Giovanna Zoccoli
- Laboratory of Physiological Regulations in Sleeping Mice, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Alessandro Silvani
- Laboratory of Physiological Regulations in Sleeping Mice, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
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