The relative effects of selective M1 muscarinic antagonists on rapid eye movement sleep

Use of remote monitoring and integrated platform for the evaluation of sleep quality in adult-onset idiopathic cervical dystonia

BACKGROUND

Up to 70% of individuals diagnosed with adult-onset idiopathic focal cervical dystonia (AOIFCD) report difficulties with sleep. Larger cohort studies using wrist-worn accelerometer devices have emerged as an alternative to smaller polysomnography studies, in order to evaluate sleep architecture.

METHODS

To measure activity during the sleep/wake cycle, individuals wore a consumer-grade wrist device (Garmin vivosmart 4) continuously over 7 days on their non-dominant wrist, while completing a daily sleep diary and standardised sleep and non-motor questionnaires via a dedicated app. Sleep measures were derived from the captured raw triaxial acceleration and heart rate values using previously published validated algorithms.

RESULTS

Data were collected from 50 individuals diagnosed with AOIFCD and 47 age- and sex-matched controls. Those with AOIFCD self-reported significantly higher levels of excessive daytime sleepiness (p = 0.04) and impaired sleep quality (p = 0.03), while accelerometer measurements found the AOIFCD cohort to have significantly longer total sleep times (p = 0.004) and time spent in NREM sleep (p = 0.009), compared to controls. Overall, there was limited agreement between wearable-derived sleep parameters, and self-reported sleep diary and visual analogue scale records.

DISCUSSION

This study shows the potential feasibility of using consumer-grade wearable devices in estimating sleep measures at scale in dystonia cohorts. Those diagnosed with AOIFCD were observed to have altered sleep architecture, notably longer total sleep time and NREM sleep, compared to controls. These findings suggest that previously reported disruptions to brainstem circuitry and serotonin neurotransmission may contribute to both motor and sleep pathophysiology.

Trihexyphenidyl increases delta activity in non-rapid eye movement sleep without impairing cognitive function in rodent models

Both human and rodent studies suggest the link between non-rapid eye movement (NREM) sleep and cognition. Recent study indicated that selective activation of cholinergic neurons in basal forebrain inhibits electroencephalogram (EEG) delta power and shortens NREM sleep. In the current study, we aimed to test the pharmacological effect of trihexyphenidyl (THP), a selective muscarinic M1 receptor antagonist, on EEG power spectra and sleep with or without the selective activation of basal forebrain cholinergic neurons. THP (1, 2, and 3 mg/kg) was administrated intraperitoneally in natural sleep phase. Basal forebrain cholinergic neurons expressing modified G protein-coupled muscarinic receptors (hM3Dq) were activated by intraperitoneal injection of clozapine-N-oxide in ChAT-IRES-Cre mice. EEG and electromyogram (EMG) signals were recorded in freely moving mice to analyze EEG power spectrum and sleep hypnogram. Y-maze and novel object recognition tests were used for testing cognition. THP 1 mg/kg significantly increased EEG delta power and facilitated NREM sleep in wildtype mice, while THP 3 mg/kg was required in ChAT-IRES-Cre mice treated with clozapine-N-oxide. THP with dosage up to 8 mg/kg did not induce cognitive impairments in wildtype mice. EEG delta power of NREM sleep is often used as an indicator of sleep depth or sleep quality, which tightly link with sleep-dependent cognition. Taken together, the data collected from rodents hinted that, THP could possibly be used as the NREM sleep facilitator in humans.

Understanding Central Nervous System Effects of Deliriant Hallucinogenic Drugs through Experimental Animal Models

Hallucinogenic drugs potently alter human behavior and have a millennia-long history of use for medicinal and religious purposes. Interest is rapidly growing in their potential as CNS modulators and therapeutic agents for brain conditions. Antimuscarinic cholinergic drugs, such as atropine and scopolamine, induce characteristic hyperactivity and dream-like hallucinations and form a separate group of hallucinogens known as "deliriants". Although atropine and scopolamine are relatively well-studied drugs in cholinergic physiology, deliriants represent the least-studied class of hallucinogens in terms of their behavioral and neurological phenotypes. As such, novel approaches and new model organisms are needed to investigate the CNS effects of these compounds. Here, we comprehensively evaluate the preclinical effects of deliriant hallucinogens in various animal models, their mechanisms of action, and potential interplay with other signaling pathways. We also parallel experimental and clinical findings on deliriant agents and outline future directions of translational research in this field.

Parkinson's disease and sleep

Sleep disorders are common in PD and many factors can contribute to disturbed nocturnal sleep and daytime sleepiness. Factors contributing to sleep disturbance include the presence of insomnia, mood or anxiety disorders, dementia, specific sleep disorders, PD motor disorders, and the effects of PD or medications. Patients who have PD should be interrogated about sleep disturbance and daytime sleepiness and preferably, because of underestimation of the severity of sleepiness or lack of awareness, patients should be interviewed in the presence of a close friend or relative. The ability to drive, if sleepiness is present, should be assessed and appropriate recommendations made. Treatment of sleepiness involves treating any underlying sleep disturbance and may involve the use of stimulant or alerting medications in the daytime.

Cerebral blood flow during spontaneous and cholinergically induced behavioral states in the sheep fetus

The sleep-wake cycle has been studied extensively in both adult and fetal mammalian species with emphasis in different areas. Fetal studies have focused on characterization of behavioral states and responses to challenges such as hypoxia, and there have been relatively fewer studies that have investigated the control of fetal behavioral state. The objective of this study was to determine whether cerebral blood flow during cholinergically induced fetal behavioral states was similar to that during spontaneous fetal behavioral states in chronically catheterized near-term sheep fetuses. Injection of carbachol (1.25 microg) into the cisterna magna increased the duration of the subsequent low-voltage electrocortical epoch. Scopolamine infusion (0.3 mg) increased the duration of the subsequent high-voltage electrocortical activity epoch. Cerebral blood flow and oxygen delivery were higher during both spontaneous and carbachol-induced low-voltage/rapid eye movement behavioral state than during spontaneous and scopolamine-induced high-voltage/non-rapid eye movement behavioral state. Thus, pharmacologic manipulation of fetal behavioral state induced a state that resembled spontaneous fetal behavioral state both electrophysiologically and metabolically. This study shows that inducing extended periods of a desired fetal behavioral state is possible and that this method may be used to study their function.

Disruption of mice sleep stages induced by low doses of organophosphorus compound soman

We have explored during 7 days, EEG spectral response and sleep pattern of mice after a mild intoxication with soman. Using an automatic staging method, we have quantified the sleep stage of the mice to identify disruptions of the sleep pattern. The 50 microg/kg dose of soman produced several effects during several time windows after intoxication. A first decrease followed by an increase of theta energy, a disturbance of slow wave sleep during 5 days and an increase of the REM sleep during the first and second day after intoxication. During the first 6h, we have observed some effects which were not consistent with a muscarinic activation and might have involved GABA-ergic system. After this early period, the observed effects were in accordance with a muscarinic activation. We observed an increase of energy in the EEG theta band during 3 days after soman injection and an increase of slow wave sleep during the second to the fifth day after soman injection.

Cholinergic modulation of inhibitory avoidance impairment induced by paradoxical sleep deprivation

1. Male Wistar rats were submitted to paradoxical sleep deprivation for 96 hr by a modified multiple platform technique. 2. Training of step-through inhibitory avoidance was performed immediately after the last day of paradoxical sleep deprivation. Twenty-four hr after training the animals were submitted to the retention test. 3. In Experiment 1, pilocarpine (4 mg/kg, i.p.) or atropine (4 mg/kg, i.p.) were administered daily during the paradoxical sleep deprivation period. Pilocarpine, but not atropine, reversed the impairment induced by PS deprivation. 4. In Experiment 2, pilocarpine (4, 8 and 12 mg/kg, i.p.) was injected 1 hr before training in order to verify if the reversal of memory impairment was an effect secondary to residual enhanced blood levels of pilocarpine during training. Acute treatment with pilocarpine, in any dose, did not reverse the impairment produced by paradoxical sleep deprivation 5. Activation of the cholinergic system during the period of deprivation is able to prevent memory deficits induced by paradoxical sleep deprivation.

The effects of 'sleep promoting agents' on behavioural state in the ovine fetus

Fetal behavioural states, with similarities to adult sleep states, exist in both the human and ovine fetus near term. The purpose of the present study was to determine the effects of intracerebral administration of pharmacologic agents, known to affect sleep states in the adult, on fetal behavioural states and physiologic correlates using the chronically catheterized ovine fetus near term. Each drug was infused into either the cisterna magna or lateral ventricle for 90 min in one of two doses. Carbachol (1.35 x 10(-5) and 4.25 x 10(-6) M) led to an increase in low-voltage ECOG, eye movement and FBM activities, while scopolamine (4.68 x 10(-4) and 1.56 x 10(-4) M) led to a decrease in low-voltage ECOG and eye movement activity with an increase in high-voltage ECOG activity. L-5-Hydroxytryptophan (5-HTP) (2.04 x 10(-3) and 6.81 x 10(-4) M) infusion led to an increase in FBM, while VIP (3.00 x 10(-7) and 1.00 x 10(-7) M) infusion had no effect on fetal behavioural state parameters. Study results indicate that fetal behavioural states can be altered pharmacologically and in a manner similar to that seen in the adult but with notable differences that may relate to species, developmental or dose-response issues.

Differential response of rapid eye movement sleep to cholinergic blockade by scopolamine in currently depressed, remitted, and normal control subjects

The degree of cholinergic dysregulation of sleep in adult depression was evaluated using scopolamine. On separate sessions, placebo and scopolamine (4.5 micrograms/kg, IM) were administered to 14 patients with unipolar major depression, 16 recovered/remitted patients, and 18 normal controls. Scopolamine increased rapid eye movement (REM) latency (RL), reduced REM activity (RA), REM density (RD), and REM duration, and increased the percentage of stage 4 sleep in all groups. There was a differential effect of scopolamine on RL, RA, and REM duration for the first REM period, and on percentage of stage 4 sleep. Whereas a primary cholinergic hyperactivity could account for the RA and RD responses, the response profile for RL was more compatible with reduced aminergic tone as the proximal cause of the cholinergic hyperactivity. Whether the sleep abnormalities observed in remitted patients reflect an underlying vulnerability for development or recurrence of depression, and/or a scar, remains to be determined.

Critical role for M3 muscarinic receptors in paradoxical sleep generation in the cat

In the cat, microdialysis application of 200 microM carbachol to the peri-locus coeruleus alpha (peri-LC alpha) of the mediodorsal pontine tegmentum produced a marked (< or = 5-fold) increase in paradoxical sleep. This effect was blocked by 5-50 microM 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP), an M1/M3-selective muscarinic receptor antagonist. In contrast, the effect was not reversed by methoctramine, an M2-selective antagonist, or pirenzepine, an M1-selective antagonist, even at concentrations as high as 500 microM. In addition, unilateral application of 5 microM 4-DAMP alone to the peri-LC alpha induced both a > 60% decrease in paradoxical sleep and a state of paradoxical sleep without atonia, whereas 50 microM pirenzepine and 500 microM methoctramine had no effect. Our findings are further evidence for the important role played by the peri-LC alpha and demonstrate a critical role for M3 muscarinic cholinergic receptors in the generation of paradoxical sleep.

Vesamicol, an acetylcholine uptake blocker in presynaptic vesicles, suppresses rapid eye movement (REM) sleep in the rat

Vesamicol inhibits acetylcholine uptake in presynaptic vesicles and reduce its release. The present study was performed in order to test the effects of this drug in a cholinergic related function as rapid eye movement (REM) sleep. Wistar male rats were implanted for sleep recordings. In addition, a stainless steel cannula was implanted into the left lateral ventricle for intracerebroventricular (ICV) injections. In experiment 1, a dose-response curve was performed. Saline or vesamicol (20, 40, 80 and 100 micrograms) were injected. Following the ICV injections, animals' sleep was recorded for 8 h. In experiment 2, after adaptation and baseline recordings, animals received 50 micrograms vesamicol ICV at 1000 hours. every 24 h for 2 consecutive days. After each injection an 8-h sleep recording session was performed. Two subsequent recovery recordings were allowed. Results obtained in experiment 1 showed a dose-response reduction of REM sleep with significant values at 80 micrograms and 100 micrograms of vesamicol. The main findings in experiment 2 were a reduction in REM sleep time and an increase in REM sleep latency. On the recovery days, a dramatic rebound of REM sleep was observed. Vesamicol behaved as an anticholinergic drug. It produced a reduction in REM sleep time and a rebound of this sleep stage after its withdrawal.

Monoaminergic and cholinergic modulation of REM-sleep timing in rats

The effects on sleep structure of systemic administration of benchmark cholinergic, serotonergic, and noradrenergic antagonists (QNB, ritanserin, metergoline, and prazosin) were characterized in rats using a new technique for identifying transitions (NRTs) from non-REM (NREM) sleep to REM sleep. In agreement with previous studies, all agents tested reduced REM-sleep expression (by 36-86%). In addition, the serotonergic and noradrenergic antagonists reduced NRT frequency (by 58-81%). The cholinergic antagonist QNB had no effect on NRT frequency. These findings suggest that blockade of serotonergic or noradrenergic receptors increases the interval between REM-sleep episodes, perhaps reducing the rate of accumulation of REM-sleep propensity. Blockade of cholinergic receptors, by contrast, decreases REM-sleep expression by interfering with REM-sleep maintenance, not by modulating REM-sleep timing. These conclusions are contrary to the predictions of a number of published models of REM-sleep timing.

Decreased muscarinic receptor binding in rat brain after paradoxical sleep deprivation: an autoradiographic study

Previous work demonstrated that paradoxical sleep deprivation (PSD) leads to a decrease in yawning behavior elicited by cholinergic agonists, suggesting that a downregulation of cholinergic muscarinic receptors may occur after PSD. More recent work using intracerebral injections of muscarinic agonists has suggested a critical role for M2 receptors in paradoxical sleep. In this study [3H]AF-DX 384 was used to investigate the effects of PSD on M2-type cholinergic receptors throughout the brain using quantitative autoradiography. After 96 h of paradoxical sleep deprivation, [3H]AF-DX 384 binding was generally reduced throughout the brain, and significantly so in the olfactory tubercle (-20%), n. accumbens (-23%), frontal caudate-putamen (-16%), islands of Callejas (-20%), piriform cortex (-24%), lateral (-26%) and medial (-24%) septum, anteromedial (-19%), ventrolateral (-22%), and lateral geniculate (-15%) nuclei of thalamus, deep layers of the superior colliculus (-15%), entorhinal cortex (-12%) and subiculum (-23%). [3H]AF-DX 384 binding was reduced in pontine structures, but not to a higher degree than in other brain areas. The observed downregulation of M2-type muscarinic receptors after PSD may be causally related to the previously reported decrease in cholinergically induced behaviors after PSD.

Selective blockade of different brain stem muscarinic receptor subtypes: effects on the sleep-wake cycle

Changes induced in the sleep-wake cycle by pontine microinjections of muscarinic antagonists were studied in freely moving rats, instrumented for chronic polygraphic recordings. Pirenzepine (PIR), methoctramine (MET) and p-fluoro-hexahydro-siladifenidol (p-F-HHSiD), which are highly selective M1, M2 and M3 antagonists, respectively, were dissolved in 0.1 microliter of sterile isotonic saline (0.2 microliter of distilled water for p-F-HHSiD) and injected into the pontine reticular nucleus, where the administration of 0.5 microgram carbachol (a mixed muscarinic agonist) induced a 52% increase in the amount of desynchronized sleep (DS) over a 6 h recording period. The blockade of M2 receptors was shown to (i) antagonize DS, by increasing its latency and decreasing its percentage, (ii) decrease slow wave sleep, and (iii) enhance wakefulness. These effects were dose-dependent. No changes in the sleep-wake cycle were observed following microinjection of M1 or M3 antagonists. The results support the hypothesis that at the brain stem level only M2 receptors are involved in sleep mechanisms and, particularly, in the generation and maintenance of DS.

Cholinergic receptor subtypes and REM sleep in animals and normal controls

As reviewed here and elsewhere in this symposium, acetylcholine, in conjunction with other neurotransmitter systems, plays a very important role in the regulation of circadian and sleep-wake states. To briefly recapitulate, several current basic concepts about the regulation of sleep-wake states include: (a) REM sleep, or at least its phasic events (eye movements and PGO spikes), are promoted by cholinergic neurons originating within the peribrachial regions [LDT/PPT] (Mitani et al., 1988; Shiromani et al., 1988; Datta et al., 1991; Shouse and Siegel, 1992); (b) REM sleep may be inhibited by noradrenergic and serotonergic neurons in the locus coeruleus and dorsal raphe, respectively (Siegel, 1989; Steriade and McCarley, 1990; Jones, 1991); (c) stages 3 and 4 (Delta) sleep are inhibited by cholinergic terminals from basal forebrain to cortex (Buzsaki et al., 1988) and from LDT/PPT to thalamus (Steriade and McCarley, 1990; Steriade et al., 1991); (d) Delta sleep is modulated by complex serotonergic mechanisms; for example, it is increased by pharmacological antagonists of 5HT2 receptors (Declerck et al., 1987; Dugovic et al., 1989; Benson et al., 1991), although the mechanism and neuroanatomical site at which this effect occurs is unknown. Given the importance of mACHR mediation of components of REM sleep, it is unfortunate that so little is known about the distribution of the various subtypes of mACHRs in brainstem areas which regulate REM sleep. mACHR subtypes have been identified by molecular, biological and pharmacological methods.(ABSTRACT TRUNCATED AT 250 WORDS)