Industrial and academic approaches to the search for alternative melatonin receptor ligands: An historical survey

The search for melatonin receptor agonists formed the main part of melatonin medicinal chemistry programs for the last three decades. In this short review, we summarize the two main aspects of these programs: the development of all the necessary tools to characterize the newly synthesized ligands at the two melatonin receptors MT1 and MT2, and the medicinal chemist's approaches to find chemically diverse ligands at these receptors. Both strategies are described. It turns out that the main source of tools were industrial laboratories, while the medicinal chemistry was mainly carried out in academia. Such complete accounts are interesting, as they delineate the spirits in which the teams were working demonstrating their strength and innovative character. Most of the programs were focused on nonselective agonists and few of them reached the market. In contrast, discovery of MT1-selective agonists and melatonergic antagonists with proven in vivo activity and MT1 or MT2-selectivity is still in its infancy, despite the considerable interest that subtype selective compounds may bring in the domain, as the physiological respective roles of the two subtypes of melatonin receptors, is still poorly understood. Poly-pharmacology applications and multitarget ligands have also been considered.

[Electrophysiological and Pharmacological Research on Neural Activity in the Neocortex and Hippocampus During Sleep]

Sleep is fundamental for living animals. Although they are not conscious during sleep, their brains are continuously working. This neural activity during sleep can be reflected by neural oscillations closely related to cognitive function. While the relationship between neural activity in sleep and cognition has been extensively investigated, it is not fully understood how neural activity in sleep and relevant memory are modulated by specific receptors. In particular, I focused on melatonin receptors and their agonist, ramelteon. While the effects of ramelteon on sleep have been widely documented, it is still poorly understood how ramelteon affects learning and memory as well as neural activity in sleep. To address this question, I first recorded neural oscillations in the neocortex of rats treated with ramelteon and found that ramelteon promoted non-rapid eye movement (NREM) sleep and increased fast gamma power in the primary motor cortex during NREM sleep. I then evaluated the behavioral performance of ramelteon-treated mice using the novel object recognition task and the spontaneous alternation task, demonstrating that ramelteon enhanced object recognition memory and spatial working memory. These results shed light on new aspects of the functions of melatonin receptors.

Methods to Assess Melatonin Receptor-Mediated Phase-Shift and Re-entrainment of Rhythmic Behaviors in Mouse Models

The neurohormone melatonin facilitates entrainment of biological rhythms to environmental light-dark conditions as well as phase-shifts of circadian rhythms in constant conditions via activation of the MT₁ and/or MT₂ receptors expressed within the suprachiasmatic nucleus of the hypothalamus. The efficacy of melatonin and related agonists to modulate biological rhythms can be assessed using two well-validated mouse models of rhythmic behaviors. These models serve as predictive measures of therapeutic efficacy for treatment of circadian phase disorders caused by internal (e.g., clock gene mutations, blindness, depression, seasonal affective disorder) or external (e.g., shift work, travel across time zones) causes in humans. Here we provide background and detailed protocols for quantitative assessment of the magnitude and efficacy of melatonin receptor ligands in mouse circadian phase-shift and re-entrainment paradigms. The utility of these models in the discovery of novel therapeutics acting on melatonin receptors will also be discussed.

Melatonin multifaceted pharmacological actions on melatonin receptors converging to abrogate COVID-19

Data indicate that controlling inflammatory responses to COVID-19 may be as important as antiviral therapies or could be an important adjunctive approach. Melatonin possesses anti-inflammation, antioxidation, and immune-enhancing features directly and/or indirectly through its own receptor signaling and is therefore well suited to reduce the severity of COVID-19. Studies have proposed that melatonin regulates COVID-19-associated proteins directly through regulation of molecules such as calmodulin (CALM) 1 and CALM 2, calreticulin (CalR), or myeloperoxidase (MPO) and/or indirectly through actions on GPCR (eg, MTNR1A, MTNR1B) and nuclear (eg, RORα, RORβ) melatonin receptor signaling. However, the exact mechanism(s) and doses by which melatonin reduces the severity of COVID-19 is still open for debate, warranting the need for further testing of melatonin in placebo-controlled randomized clinical trials for COVID-19.

Effects of Ramelteon on the Prevention of Postoperative Delirium in Older Patients Undergoing Orthopedic Surgery: The RECOVER Randomized Controlled Trial

OBJECTIVES

Postoperative delirium, associated with negative consequences including longer hospital stays and worse cognitive and physical outcomes, is frequently accompanied by sleep-wake disturbance. Our objective was to evaluate the efficacy and short-term safety of ramelteon, a melatonin receptor agonist, for the prevention of postoperative delirium in older patients undergoing orthopedic surgery.

DESIGN

A quadruple-masked randomized placebo-controlled trial (Clinical Trials.gov NCT02324153) conducted from March 2017 to June 2019.

SETTING

Tertiary academic medical center.

PARTICIPANTS

Patients aged 65 years or older, undergoing elective primary or revision hip or knee replacement.

INTERVENTION

Ramelteon (8 mg) or placebo MEASUREMENTS: Eighty participants were randomized to an oral gel cap of ramelteon or placebo for 3 consecutive nights starting the night before surgery. Trained research staff conducted delirium assessments for 3 consecutive days starting on postoperative day (POD) 0, after recovery from anesthesia, and on to POD2. A delirium diagnosis was based upon DSM-5 criteria determined by expert panel consensus.

RESULTS

Of 80 participants, five withdrew consent (one placebo, four ramelteon) and four were excluded (four ramelteon) after randomization. Delirium incidence during the 2 days following surgery was 7% (5 of 71) with no difference between the ramelteon versus placebo: 9% (3 of 33) and 5% (2 of 38), respectively. The adjusted odds ratio for postoperative delirium as a function of assignment to the ramelteon treatment arm was 1.28 (95% confidence interval: 0.21-7.93; z-value 0.27; p-value = 0.79). Adverse events were similar between the two groups.

CONCLUSION

In older patients undergoing elective primary or revision hip or knee replacement, ramelteon was not efficacious in preventing postoperative delirium.

Classical and non-classical melatonin receptor agonist-directed micellization of bipyridinium-based supramolecular amphiphiles in water

The addition of molecular recognition units into structures of amphiphiles is a means by which soft matter capable of undergoing template-directed micellization can be obtained. These supramolecular amphiphiles can bind with molecular templates using non-covalent bonding interactions, forming host-guest complexes that hold the amphiphiles together as they undergo micellization. In most cases, such templates are synthesized and designed for a specific molecular recognition motif. It is not clear, however, to what extent these types of amphiphile systems are responsive to members of a biologically derived class of molecular targets, for example, melatonin receptor agonists and their numerous isosteres. Herein, we describe the template-directed micellization and arrangement at the air-water interface of a bipyridinium-based gemini surfactant, driven by the influence of donor-acceptor CT interactions with a series of bioactive classical and non-classical melatonin isosteres. Under the conditions of templation by either 5-methoxytryptophol, N-acetylserotonin, N-acetyltryptamine, or the pharmaceutical agent agomelatine, favorable Gibbs free energies of micellization were observed with decreases in CMC by up to 70%, and concomitant increases of 28% in surface pressure, and decreases of 20% in contact angle versus untemplated solutions. Solid state thermochromic transition temperatures for inkjet-printed patterns of the templated amphiphile solutions were inversely correlated with trends observed for their respective CMCs, and exhibited no correlation to their binding constants. These findings contend for the generalizable use of melatonin receptor agonists as targets and/or templates for chemical systems, which rely on π-stacking donor-acceptor CT interactions in water to facilitate the actions of binding, sequestration, or template-directed self-assembly.

Structure-based discovery of potent and selective melatonin receptor agonists

Melatonin receptors MT1 and MT2 are involved in synchronizing circadian rhythms and are important targets for treating sleep and mood disorders, type-2 diabetes and cancer. Here, we performed large scale structure-based virtual screening for new ligand chemotypes using recently solved high-resolution 3D crystal structures of agonist-bound MT receptors. Experimental testing of 62 screening candidates yielded the discovery of 10 new agonist chemotypes with sub-micromolar potency at MT receptors, with compound 21 reaching EC50 of 0.36 nM. Six of these molecules displayed selectivity for MT2 over MT1. Moreover, two most potent agonists, including 21 and a close derivative of melatonin, 28, had dramatically reduced arrestin recruitment at MT2, while compound 37 was devoid of Gi signaling at MT1, implying biased signaling. This study validates the suitability of the agonist-bound orthosteric pocket in the MT receptor structures for the structure-based discovery of selective agonists.

The efficacy of melatonin and melatonin agonists in insomnia - An umbrella review

We conducted an umbrella review to summarize all available systematic reviews and meta-analyses investigating the efficacy of melatonin and melatonin agonists in primary and comorbid insomnia disorders. Two independent reviewers conducted a search of Pubmed, EMBASE, Cochrane Database of Systematic Reviews, Google Scholar, PROSPERO and grey literature from inception to July 2018. Methodological quality was assessed using the revised Assessment of Multiple Systematic Reviews Instrument. Eighteen studies were found, with methodological quality ranging from Moderate to Critically Low. Of the twelve papers evaluating melatonin, there is statistically significant improvement in sleep latency and total sleep time, with a lack of consensus on whether these are clinically meaningful. Similar results are observed across the three reviews on ramelteon. The evidence for other melatonin agonists is sparse. We conclude that existing evidence is limited by disparate methodological quality of the papers, as well as a lack of consensus regarding the type, definition and interpretation of outcome measures in the evaluation of efficacy for insomnia.

Melatonin for the treatment of gastroesophageal reflux disease; protocol for a systematic review and meta-analysis

BACKGROUND

Melatonin generated in the gastrointestinal tract has mucosal protective effect with inhibiting gastric acid secretion, while increasing gastrin release, which in turn stimulates the contractility of lower esophageal sphincter. Gastroesophageal reflux disease (GERD) is also known to have association with sleep disturbance. However, melatonin or melatonin receptor agonist has not been included in the treatment of GERD. This study aimed to evaluate the efficacy of melatonin for the treatment of GERD.

METHODS

We will search the core databases [MEDLINE (through PubMed), the Cochrane Library, and Embase] from their inception to December 2018 by 2 independent evaluators. The P.I.C.O. is as follows; Patients: who have GERD, Intervention: melatonin or melatonin receptor agonist treatment, Comparison: patients without melatonin or melatonin receptor agonist treatment, Outcome: clinical indices (or crude number or proportion of improvement) for the evaluation of symptomatic improvement which enable comparison of efficacy between patients with melatonin or melatonin receptor agonist and the control group. All types of study design will be sought with full-text will be included. The risk of bias will be assessed using the ROBINS-I tool. Descriptive data synthesis is planned and quantitative synthesis will be used if the included studies are sufficiently homogenous. Publication bias will be assessed with quantitative analyses if more than 10 articles are enrolled.

RESULTS

The results will provide evidence for the efficacy of melatonin or melatonin receptor agonist for the treatment of GERD.

CONCLUSION

This study will provide evidence of melatonin or melatonin receptor agonist treatment for GERD.

Melatonin Receptor Agonists as the "Perioceutics" Agents for Periodontal Disease through Modulation of Porphyromonas gingivalis Virulence and Inflammatory Response

Aim

“Perioceutics” including antimicrobial therapy and host modulatory therapy has emerged as a vital adjunctive treatment of periodontal disease. Melatonin level was significantly reduced in patients with periodontal diseases suggesting melatonin could be applied as a potential “perioceutics” treatment of periodontal diseases. This study aims to investigate the effects of melatonin receptor agonists (melatonin and ramelteon) on Porphyromonas gingivalis virulence and Porphyromonas gingivalis-derived lipopolysaccharide (Pg-LPS)-induced inflammation.

Methods

Effects of melatonin receptor agonists on Porphyromonas gingivalis planktonic cultures were determined by microplate dilution assays. Formation, reduction, and viability of Porphyromonas gingivalis biofilms were detected by crystal violet staining and MTT assays, respectively. Meanwhile, biofilms formation was also observed by confocal laser scanning microscopy (CLSM). The effects on gingipains and hemolytic activities of Porphyromonas gingivalis were evaluated using chromogenic peptides and sheep erythrocytes. The mRNA expression of virulence and iron/heme utilization was assessed using RT-PCR. In addition, cell viability of melatonin receptor agonists on human gingival fibroblasts (HGFs) was evaluated by MTT assays. After pretreatment of melatonin receptor agonists, HGFs were stimulated with Pg-LPS and then release of cytokines (IL-6 and lL-8) was measured by enzyme-linked immunosorbent assay (ELISA).

Results

Melatonin and ramelteon did exhibit antimicrobial effects against planktonic culture. Importantly, they inhibited biofilm formation, reduced the established biofilms, and decreased biofilm viability of Porphyromonas gingivalis. Furthermore, they at sub-minimum inhibitory concentration (sub-MIC) concentrations markedly inhibited the proteinase activities of gingipains and hemolysis in a dose-dependent manner. They at sub-MIC concentrations significantly inhibited the mRNA expression of virulence factors (kgp, rgpA, rgpB, hagA, and ragA), while increasing the mRNA expression of ferritin (ftn) or hemolysin (hem). They did not show obvious cytotoxicity toward HGFs. They inhibited Pg-LPS-induced IL-6 and IL-8 secretion, which was reversed by luzindole, the melatonin receptor antagonist.

Conclusion

Melatonin receptor agonists can inhibit planktonic and biofilm growth of Porphyromonas gingivalis by affecting the virulent properties, as well as Pg-LPS-induced inflammatory response. Our study provides new evidence that melatonin receptor agonists might be useful as novel “perioceutics” agents to prevent and treat Porphyromonas gingivalis-associated periodontal diseases.

Melatonin, but not melatonin receptor agonists Neu-P11 and Neu-P67, attenuates TNBS-induced colitis in mice

Melatonin is known as a strong antioxidant and possesses anti-inflammatory properties. Recently, melatonin was shown to improve colitis in animal models of inflammatory bowel diseases. The aim of the present study was to characterize the role of melatonin receptors (MT) in the anti-inflammatory effect of melatonin and to assess the anti-inflammatory potential of two novel MT receptor agonists, Neu-P11 and Neu-P67, in the mouse model of trinitrobenzenesulfonic acid (TNBS)-induced colitis. Colitis was induced on day 1 by intracolonic (i.c.) administration of TNBS in 30 % ethanol in saline. Melatonin (4 mg/kg, per os (p.o.)), Neu-P11 (20 mg/kg, p.o.; 50 mg/kg, intraperitoneally (i.p.), 50 mg/kg, i.c.), and Neu-P67 (20 mg/kg, p.o.) were given twice daily for 3 days. Luzindole (5 mg/kg, i.p.) was injected 15 min prior to melatonin administration. On day 4, macroscopic and microscopic damage scores were assessed and myeloperoxidase (MPO) activity quantified using O-dianisidine-based assay. Melatonin significantly attenuated colitis in mice, as indicated by the macroscopic score (1.90 ± 0.34 vs. 3.82 ± 0.62 for melatonin- and TNBS-treated mice, respectively), ulcer score (0.87 ± 0.18 vs. 1.31 ± 0.19, respectively), and MPO activity (4.68 ± 0.70 vs.6.26 ± 0.94, respectively). Luzindole, a MT receptor antagonist, did not inhibit the anti-inflammatory effect of melatonin (macroscopic score 1.12 ± 0.22, ulcer score 0.50 ± 0.16); however, luzindole increased MPO activity (7.57 ± 1.05). MT receptor agonists Neu-P11 and Neu-P67 did not improve inflammation induced by TNBS. Melatonin, but not MT receptor agonists, exerts potent anti-inflammatory action in acute TNBS-induced colitis. Our data suggests that melatonin attenuates colitis by additional, MT receptor-independent pathways.

A Cluster Headache Responsive to Ramelteon, a Selective Melatonin MT1/MT2 Receptor Agonist

Patients with cluster headaches occasionally fail to respond to conventional preventive treatments. We herein report a case of a patient with a cluster headache in which the symptoms were refractory to conventional preventive treatments except for high-dose glucocorticoids. The headache attacks occurred daily while sleeping, thus the patient suffered from insomnia. Ramelteon, a selective melatonin receptor agonist and a member of a new class of insomnia therapies, completely suppressed the attacks during sleep and provided rapid relief from insomnia. This is the first English case report to describe the efficacy of ramelteon as a preventive treatment for cluster headaches.

New Developments in Insomnia Medications of Relevance to Mental Health Disorders

Many insomnia medications with high specificity have become available recently. They provide a window into the clinical effects of modulating specific brain systems and establish a new guiding principal for conceptualizing insomnia medications: "mechanism matters." A new paradigm for insomnia therapy in which specific drugs are selected to target the specific type of sleep difficulty for each patient includes administering specific treatments for patients with insomnia comorbid with particular psychiatric disorders. This article reviews insomnia medications and discusses the implications for optimizing the treatment of insomnia occurring comorbid with psychiatric conditions.

Tasimelteon for non-24-hour sleep-wake disorder in totally blind people (SET and RESET): two multicentre, randomised, double-masked, placebo-controlled phase 3 trials

BACKGROUND

Most totally blind people have non-24-hour sleep-wake disorder (non-24), a rare circadian rhythm disorder caused by an inability of light to reset their circadian pacemaker. In two consecutive placebo-controlled trials (SET and RESET), we assessed safety and efficacy (in terms of circadian entrainment and maintenance) of once-daily tasimelteon, a novel dual-melatonin receptor agonist.

METHODS

We undertook the placebo-controlled, randomised, double-masked trials in 27 US and six German clinical research centres and sleep centres. We screened totally blind adults (18-75 years of age), who were eligible for the randomisation phase of SET if they had a non-24-hour circadian period (τ) of 24·25 h or longer (95% CI greater than 24·0 and up to 24·9 h), as calculated from measurements of urinary 6-sulphatoxymelatonin rhythms. For SET, we used block randomisation to assign patients (1:1) to receive tasimelteon (20 mg) or placebo every 24 h at a fixed clock time 1 h before target bedtime for 26 weeks. Patients who entered the open-label group receiving tasimelteon in SET or who did not meet the SET inclusion criteria but did meet the RESET inclusion criteria were screened for RESET. A subset of the patients who entered the open-label group before the RESET study and who had eligible τ values were screened for RESET after completing the open-label treatment. In RESET, we withdrew tasimelteon in a randomised manner (1:1) in patients who responded (ie, entrained) after a tasimelteon run-in period. Entrainment was defined as having τ of 24·1 h or less and a 95% CI that included 24·0 h. In SET, the primary endpoint was the proportion of entrained patients, assessed in the intention-to-treat population. The planned step-down primary endpoint assessed the proportion of patients who had a clinical response (entrainment at month 1 or month 7 plus clinical improvement, measured by the Non-24 Clinical Response Scale). In RESET, the primary endpoint was the proportion of non-entrained patients, assessed in the intention-to-treat population. Safety assessments included adverse events and clinical laboratory measures, assessed in all treated patients. These trials are registered with ClinicalTrials.gov, numbers NCT01163032 and NCT01430754.

FINDINGS

Between Aug 25, 2010, and July 5, 2012, we screened 391 totally blind patients for SET, of whom 84 (22%) were assigned to receive tasimelteon (n=42) or placebo (n=42). Two patients in the tasimelteon group and four in the placebo group discontinued the study before τ was measured, due to adverse events, withdrawal of consent, and a protocol deviation. Circadian entrainment occurred in eight (20%) of 40 patients in the tasimelteon group compared with one (3%) of 38 patients in the placebo group at month 1 (difference 17%, 95% CI 3·2-31·6; p=0·0171). Nine (24%) of 38 patients showed a clinical response, compared with none of 34 in the placebo group (difference 24%, 95% CI 8·4-39·0; p=0·0028). Between Sept 15, 2011, and Oct 4, 2012, we screened 58 patients for eligibility in RESET, 48 (83%) of whom had τ assessed and entered the open-label tasimelteon run-in phase. 24 (50%) patients entrained, and 20 (34%) were enrolled in the randomisation phase. Two (20%) of ten patients who were withdrawn to placebo remained entrained compared with nine (90%) of ten who continued to receive tasimelteon (difference 70%, 95% CI 26·4-100·0; p=0·0026). No deaths were reported in either study, and discontinuation rates due to adverse events were comparable between the tasimelteon (3 [6%] of 52 patients) and placebo (2 [4%] of 52 patients) treatment courses. The most common side-effects associated with tasimelteon in SET were headache (7 [17%] of 42 patients given tasimelteon vs 3 [7%] of 42 patients given placebo), elevated liver enzymes (4 [10%] vs 2 [5%]), nightmares or abnormal dreams (4 [10%] vs none), upper respiratory tract infection (3 [7%] vs none], and urinary tract infections (3 [7%] vs 1 [2%]).

INTERPRETATION

Once-daily tasimelteon can entrain totally blind people with non-24; however, continued tasimelteon treatment is necessary to maintain these improvements.

FUNDING

Vanda Pharmaceuticals.

[Melatonin receptor agonist]

Melatonin is a hormone secreted by the pineal gland and is involved in the regulation of human sleep-wake cycle and circadian rhythms. The melatonin MT1 and MT2 receptors located in the suprachiasmatic nucleus in the hypothalamus play a pivotal role in the sleep-wake regulation. Based on the fact that MT1 receptors are involved in human sleep onset process, melatonin receptor agonists have been developed to treat insomnia. In this article, we first reviewed functions of melatonin receptors with special reference to MT1 and MT2, and properties and clinical application of melatonin receptor agonists as hypnotics.

Pharmacokinetics of the dual melatonin receptor agonist tasimelteon in subjects with hepatic or renal impairment

Tasimelteon is a circadian regulator that resets the master clock in the suprachiasmatic nuclei of the hypothalamus by binding to both melatonin MT1 and MT2 receptors making it a dual melatonin receptor agonist. Tasimelteon has been approved by the United States Food and Drug Administration for the treatment of Non-24-Hour Sleep-Wake Disorder (Non-24). Two prospective, single-center, open-label studies evaluated the pharmacokinetics of tasimelteon and its main metabolites after a single 20 mg dose administered to subjects with mild or moderate hepatic impairment or severe renal impairment, including subjects on dialysis compared to healthy controls. In subjects with mild or moderate hepatic impairment, exposure to tasimelteon after a single 20 mg dose, as measured by area under the plasma concentration-time curve to infinity, was increased by approximately 2-fold. There was no apparent relationship between tasimelteon clearance and renal function. No safety concerns were apparent in either study. Based on these results, the changes in the pharmacokinetics of tasimelteon due to mild or moderate hepatic or severe renal impairment are not considered clinically relevant, and no dose adjustment is necessary in these patients.

Therapeutic effects of melatonin receptor agonists on sleep and comorbid disorders

Several melatonin receptors agonists (ramelteon, prolonged-release melatonin, agomelatine and tasimelteon) have recently become available for the treatment of insomnia, depression and circadian rhythms sleep-wake disorders. The efficacy and safety profiles of these compounds in the treatment of the indicated disorders are reviewed. Accumulating evidence indicates that sleep-wake disorders and co-existing medical conditions are mutually exacerbating. This understanding has now been incorporated into the new Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5). Therefore, when evaluating the risk/benefit ratio of sleep drugs, it is pertinent to also evaluate their effects on wake and comorbid condition. Beneficial effects of melatonin receptor agonists on comorbid neurological, psychiatric, cardiovascular and metabolic symptomatology beyond sleep regulation are also described. The review underlines the beneficial value of enhancing physiological sleep in comorbid conditions.

The melatonin agonist ramelteon induces duration-dependent clock gene expression through cAMP signaling in pancreatic INS-1 β-cells

Prolonged exposure to melatonin improves glycemic control in animals. Although glucose metabolism is controlled by circadian clock genes, little is known about the role of melatonin signaling and its duration in the regulation of clock gene expression in pancreatic β-cells. Activation of MT1 and MT2 melatonin receptors inhibits cAMP signaling, which mediates clock gene expression. Therefore, this study investigated exposure duration-dependent alterations in cAMP element-binding protein (CREB) phosphorylation and clock gene expression that occur during and after exposure to ramelteon, a selective melatonin agonist used to treat insomnia. In rat INS-1 cells, a pancreatic β-cell line endogenously expressing melatonin receptors, ramelteon persistently decreased CREB phosphorylation during the treatment period (2-14 h), whereas the subsequent washout induced an enhancement of forskolin-stimulated CREB phosphorylation in a duration- and concentration-dependent manner. This augmentation was blocked by forskolin or the melatonin receptor antagonist luzindole. Similarly, gene expression analyses of 7 clock genes revealed the duration dependency of the effects of ramelteon on Rev-erbα and Bmal1 expression through melatonin receptor-mediated cAMP signaling; longer exposure times (14 h) resulted in greater increases in the expression and signaling of Rev-erbα, which is related to β-cell functions. Interestingly, this led to amplified oscillatory Rev-erbα and Bmal1 expression after agonist washout and forskolin stimulation. These results provide new insights into the duration-dependent effects of ramelteon on clock gene expression in INS-1 cells and may improve the understanding of its effect in vivo. The applicability of these results to pancreatic islets awaits further investigation.

Antinociceptive effects of novel melatonin receptor agonists in mouse models of abdominal pain

AIM: To characterize the antinociceptive action of the novel melatonin receptor (MT) agonists, Neu-P11 and Neu-P12 in animal models of visceral pain.

METHODS: Visceral pain was induced by intracolonic (ic) application of mustard oil or capsaicin solution or by intraperitoneal (ip) administration of acetic acid. Neu-P11, Neu-P12, or melatonin were given ip or orally and their effects on pain-induced behavioral responses were evaluated. To identify the receptors involved, the non-selective MT1/MT2 receptor antagonist luzindole, the MT2 receptor antagonist 4-P-PDOT, or the μ-opioid receptor antagonist naloxone were injected ip or intracerebroventricularly (icv) prior to the induction of pain.

RESULTS: Orally and ip administered melatonin, Neu-P11, and Neu-P12 reduced pain responses in a dose-dependent manner. Neu-P12 was more effective and displayed longer duration of action compared to melatonin. The antinociceptive effects of Neu-P11 or Neu-P12 were antagonized by ip or icv. administered naloxone. Intracerebroventricularly, but not ip administration of luzindole or 4-P-PDOT blocked the antinociceptive actions of Neu-P11 or Neu-P12.

CONCLUSION: Neu-P12 produced the most potent and long-lasting antinociceptive effect. Further development of Neu-P12 for future treatment of abdominal pain seems promising.

[Modern approaches to the synchronization of circadian rhythms in treatment of depression]

In this review, we have analyzed the association between chronobiological disorders and depressive symptoms, and outlined new antidepressant therapeutic strategies aimed at restoring normal functioning of the circadian system. It is specifically noted that the drug valdoxan, an agonist of melatonin receptors and selective antagonist of serotoninergic 5-HT2C receptors has chronobiotic,antidepressive and anxiolytic action. In its antidepressive effect, valdoxan is comparable to venlafaxine, fluoxetine and sertraline.Recurrences of depression is noted in fewer patients (23,9 %) treated with valdoxan compared to placebo (50,0 %). The drug improves sleep quality as well. As the drug does not cause the increase in serotonin levels, it has considerably less side-effects of the gastrointestinal tract, sexual sphere, or metabolic processes, characteristic of many other antidepressants.

Agomelatine: a review of adverse effects

More pharmacovigilance data on agomelatine became available in 2012. The main sources of information were surveillance data from the French national monitoring system, EU periodic safety update reports (PSURs), and the European pharmacovigilance database. The principal adverse effects of agomelatine consist of hepatic, pancreatic, neuropsychiatric, muscular and cutaneous disorders. The harms associated with agomelatine, which has no proven efficacy in depression, clearly outweigh the benefits. Until regulatory agencies decide to withdraw agomelatine from the market, it is up to healthcare professionals to protect patients from this unnecessarily dangerous drug.

Use of ramelteon for the treatment of secondary REM sleep behavior disorder

We used ramelteon to treat two patients with secondary REM sleep behavior disorder (RBD) complications along with neurodegenerative diseases including multiple system atrophy and Parkinson's disease. These two patients not only improved in terms of their clinical RBD symptoms but also exhibited a decrease in the proportion of REM sleep without atonia (from 8.5% to 3.5% and from 10.9% to 3.9% in the two patients). Although clonazepam is the standard first-line therapy for the treatment of RBD, ramelteon might be an effective treatment alternative in patients with RBD who cannot take clonazepam due to either ineffectiveness or adverse effects.

[Present status and future of hypnotic drug treatment for insomnia]

Pharmacological treatments of insomnia have become safer since the first benzodiazepine receptor agonist (BzRA) hypnotic was introduced in the 1960's. Though BzRAs could hardly cause a fatal condition even in cases of overdosing, they had inherited the arguments on addiction and withdrawal from the prior studies of barbiturate hypnotics that indicated they are strongly addictive. In the 2000s, it was repeatedly demonstrated that insomnia as well as sleep deprivation underlie the development and deterioration of comorbid diseases such as hypertension, cardiovascular diseases, diabetes and depression, and that the proper use of hypnotic drugs is unlikely to cause tolerance, addiction nor rebound phenomena, but likely to be associated with improvement of QOL. Thus, the 2005's consensus report on chronic insomnia by NIH has recommended general physicians to facilitate insomnia treatment to prevent the development of physical and/or mental disorders. The author reviewed in this article the efficacy and side effects of BzRA hypnotics, a hypnotic drug therapy combined with cognitive and behavioral interventions, uses of melatonin receptor agonist in general and sleep medicine practices, and future utilization of newly-developed orexin antagonists for insomnia treatment.

[Melatonin as a regulator of human sleep and circadian systems]

Melatonin(N-acetyl-5-methoxytryptamine) is synthesized from tryptophan and is intensively secreted into the blood only in darkness (nighttime) by the pineal gland. Melatonin is not only the most reliable marker of internal circadian phase but also a potent sleep-promoting and circadian phase regulatory agent in humans. There is evidence that daytime administered melatonin is able to exhibit short-acting hypnagogic effect and phase-shifting of the circadian rhythms such that sleep timing and associated various physiological functions realign at a new desired phase. Under favor of these properties, melatonin and melatonin receptor agonists have been shown to be potent therapeutic agents for the treatment of circadian rhythm sleep disorders and some type of insomnia.

Melatonin receptor agonists: new options for insomnia and depression treatment

The circadian nature of melatonin (MLT) secretion, coupled with the localization of MLT receptors to the suprachiasmatic nucleus, has led to numerous studies of the role of MLT in modulation of the sleep-wake cycle and circadian rhythms in humans. Although much more needs to be understood about the various functions exerted by MLT and its mechanisms of action, three therapeutic agents (ramelteon, prolonged-release MLT, and agomelatine) are already in use, and MLT receptor agonists are now appearing as new promising treatment options for sleep and circadian-rhythm related disorders. In this review, emphasis has been placed on medicinal chemistry strategies leading to MLT receptor agonists, and on the evidence supporting therapeutic efficacy of compounds undergoing clinical evaluation. A wide range of clinical trials demonstrated that ramelteon, prolonged-release MLT and tasimelteon have sleep-promoting effects, providing an important treatment option for insomnia and transient insomnia, even if the improvements of sleep maintenance appear moderate. Well-documented effects of agomelatine suggest that this MLT agonist offers an attractive alternative for the treatment of depression, combining efficacy with a favorable side effect profile. Despite a large number of high affinity nonselective MLT receptor agonists, only limited data on MT₁ or MT₂ subtype-selective compounds are available up to now. Administration of the MT₂-selective agonist IIK7 to rats has proved to decrease NREM sleep onset latency, suggesting that MT₂ receptor subtype is involved in the acute sleep-promoting action of MLT; rigorous clinical studies are needed to demonstrate this hypothesis. Further clinical candidates based on selective activation of MT₁ or MT₂ receptors are expected in coming years.

Vertebrate melanophores as potential model for drug discovery and development: a review

Drug discovery in skin pharmacotherapy is an enormous, continually expanding field. Researchers are developing novel and sensitive pharmaceutical products and drugs that target specific receptors to elicit concerted and appropriate responses. The pigment-bearing cells called melanophores have a significant contribution to make in this field. Melanophores, which contain the dark brown or black pigment melanin, constitute an important class of chromatophores. They are highly specialized in the bidirectional and coordinated translocation of pigment granules when given an appropriate stimulus. The pigment granules can be stimulated to undergo rapid dispersion throughout the melanophores, making the cell appear dark, or to aggregate at the center, making the cell appear light. The major signals involved in pigment transport within the melanophores are dependent on a special class of cell surface receptors called G-protein-coupled receptors (GPCRs). Many of these receptors of adrenaline, acetylcholine, histamine, serotonin, endothelin and melatonin have been found on melanophores. They are believed to have clinical relevance to skin-related ailments and therefore have become targets for high throughput screening projects. The selective screening of these receptors requires the recognition of particular ligands, agonists and antagonists and the characterization of their effects on pigment motility within the cells. The mechanism of skin pigmentation is incredibly intricate, but it would be a considerable step forward to unravel its underlying physiological mechanism. This would provide an experimental basis for new pharmacotherapies for dermatological anomalies. The discernible stimuli that can trigger a variety of intracellular signals affecting pigment granule movement primarily include neurotransmitters and hormones. This review focuses on the role of the hormone and neurotransmitter signals involved in pigment movement in terms of the pharmacology of the specific receptors.

[Melatoninergic antidepressant valdoxan]

Data on the pharmacological properties, mechanism of action, and clinical advantages of the new antidepressant drug valdoxan capable of selectively stimulating melatonin receptors are presented. The drug effect is compared to the action of epiphyseal hormone melatonin and traditional antidepressants.

In vitro and in vivo antitumor activity of melatonin receptor agonists

Melatonin has been shown to inhibit the proliferation of estrogen receptor α (ERα)-positive human breast cancer cells in vitro and suppress the growth of carcinogen-induced mammary tumors in rats. Melatonin's antiproliferative effect is mediated, at least in part, through the MT1 melatonin receptor and mechanisms involving modulation of the estrogen-signaling pathway. To develop melatonin analogs with greater therapeutic effects, we have examined the in vitro and in vivo antimitotic activity of two MT1/MT2 melatonin receptor agonists, S23219-1 and S23478-1. In our studies, both agonists are quite effective at suppressing the growth of MCF-7 human breast cancer cells. At a concentration of 10⁻⁶ m, S23219-1 and S23478-1 inhibited the growth of MCF-7 cells by 60% and 73%, respectively. However, S23478-1 is more effective than melatonin and S23219-1 at repressing the expression and transactivation of the ERα, and modulating the expression of pancreatic spasmolytic polypeptide (pS2), an estrogen-regulated gene. The melatonin agonist S23478-1 exhibited enhanced antitumor potency in the subsequent studies in our animal model. At a dosage of 25 mg/kg/day, S23478-1 is more efficacious than melatonin at inducing regression of the established N-nitroso-N-methyl-urea-induced rat mammary tumors. This dose of S23478-1 (25 mg/kg/day) generated a significant (P < 0.05) overall regression response of 52%. Furthermore, at this dosage, S23478-1 is more effective than melatonin at suppressing the estrogen-signaling pathway and promoting tumor cell apoptosis, significantly increasing the expression of the pro-apoptotic protein Bax, while decreasing the expression of ERα and the anti-apoptotic protein Bcl-2.

Acute and chronic effects of ramelteon in rhesus monkeys (Macaca mulatta): dependence liability studies

The acute and chronic effects of ramelteon, an MT1/MT2 receptor agonist, were evaluated in rhesus monkeys (Macaca mulatta) to assess discriminative stimulus effects in comparison with traditional benzodiazepine receptor agonists and to assess physical dependence potential. Discriminative effects of ramelteon were compared with midazolam in untreated monkeys and in diazepam-dependent monkeys that discriminated flumazenil. Dependence potential of ramelteon after daily 1-year administration (and intermittent discontinuation) was evaluated with standard operant procedures. Ramelteon did not produce benzodiazepine-like discriminative stimulus effects at doses up to 10 mg/kg. Long-term treatment or its discontinuation had no significant effect on spontaneous behavior, operant behavior, body weight, motor activity, or posture. These findings suggest that ramelteon is not likely to have benzodiazepine-like abuse or dependence liability.

Tasimelteon, a melatonin agonist for the treatment of insomnia and circadian rhythm sleep disorders

Tasimelteon, developed by Vanda Pharmaceuticals Inc under license from Bristol-Myers Squibb Co, is a melatonin receptor agonist. Because of the high density of melatonin receptors in the circadian pacemaker, the suprachiasmatic nucleus, melatonergic actions can phase-shift circadian rhythms and promote sleep. Tasimelteon was effective in reducing sleep onset latency (in phase II and III clinical trials) and in resetting the circadian melatonin rhythm (in phase II trials), which indicated its potential suitability as treatment for jet lag, shift work and circadian rhythm sleep disorders. Statistically significant improvements in sleep maintenance have also been observed with the drug. Tasimelteon has been claimed to be useful in the treatment of depression, and preclinical evidence in this respect is to be confirmed in a phase II clinical trial, which was ready to be initiated at the time of publication. It is plausible that the drug may be effective in the treatment of depressive disorders, at least those that are related to circadian dysfunction, and that it may attenuate sleep problems in depressed patients of different subtypes. A general suitability in mitigating other symptoms of major depressive disorder cannot be deduced from the actions of tasimelteon via the melatonin receptors MT1 and MT2. The drug is well tolerated, does not induce impairment of next-day functioning or dependence, and seems to be safe in short-term treatment; however, toxicological data would be required for assessing its long-term safety.

Ramelteon: application withdrawn. Ramelteon in insomnia: withdrawal of marketing application in patients' best interests

The European Committee for Medicinal Products for Human Use (CHMP) has issued a negative opinion on the use of the melatonin receptor agonist ramelteon in insomnia, due to its unfavourable risk-benefit balance. In France, melatonin itself is licensed for use in this indication.

Effects of ramelteon 8 mg on objective sleep latency in adults with chronic insomnia on nights 1 and 2: pooled analysis

OBJECTIVE

Ramelteon is an MT(1)/MT(2) melatonin receptor agonist indicated for the treatment of insomnia characterized by difficulty with sleep onset. In previous clinical studies, ramelteon reduced latency to persistent sleep (LPS) in subjects with chronic insomnia. The goal of the current analysis was to determine the average reduction in LPS and overall adverse event profile for subjects taking ramelteon 8 mg.

RESEARCH DESIGN AND METHODS

This pooled analysis examined four randomized, double-blind, placebo-controlled clinical trials of ramelteon in subjects with chronic insomnia. The analysis included adults (age 18-83 years) with chronic insomnia who took ramelteon 8 mg or placebo. The primary endpoint of each trial was mean LPS, measured by polysomnography (PSG) on nights 1 and 2. Adverse events were collected for all subjects for the duration of each trial.

RESULTS

Efficacy data were available for 566 subjects who took ramelteon 8 mg (mean age 46.7 years) and 556 subjects who took placebo (mean age 47.8 years). Mean LPS at baseline was 66.6 min for the placebo group and 66.9 min for the ramelteon group. At nights 1 and 2, mean LPS for the ramelteon 8 mg group (30.2 min) was significantly less than the mean LPS for the placebo group (43.3 min). The least squares mean difference from placebo was -13.1 min (p < 0.001). Headache (8.9% ramelteon 8 mg, 8.8% placebo) and somnolence (3.5% ramelteon 8 mg, 0.7% placebo) were the most common adverse events.

CONCLUSIONS

Ramelteon 8 mg, on average, reduced LPS by approximately 13 min more than placebo on nights 1 and 2 of treatment in adults with chronic insomnia. Ramelteon was well tolerated with a low incidence of adverse events. This mean reduction in LPS versus placebo is similar to what has been reported for other classes of insomnia medications. However, these results reflect nights 1 and 2 of treatment and may not be representative of longer treatments.

The role of eszopiclone in the treatment of insomnia

INTRODUCTION

Insomnia is a common and underdiagnosed condition that can result in significant economic and clinical consequences. Despite numerous behavioral and pharmacotherapeutic treatment options available for insomnia, few receive adequate treatment, and sleep maintenance (staying asleep) remains a significant problem. To date, available sedative-hypnotic agents have limitations that have lead to inadequate treatment of insomnia. This review provides an overview of eszopiclone and its role in the treatment of insomnia.

METHODS

Electronic databases (MEDLINE, EMBASE, International Pharmaceutical Abstracts) were searched for applicable primary literature and review articles.

RESULTS

Mechanisms of action at the gamma-amino butyric acid (GABA) receptor sites and pharmacologic and pharmacokinetic characteristics are presented. Eszopiclone, a nonbenzodiazepine S-enantiomer of racemic zopiclone, is highlighted as the first sedative-hypnotic agent to be approved by the United States Food and Drug Administration for the treatment of sleep onset latency and sleep maintenance insomnia with no short-term restrictions. Recently, the European Medicines Agency recommended marketing authorization of eszopiclone.

CONCLUSION

Eszopiclone has been shown to be an efficacious and cost-effective option for the treatment of transient and chronic insomnia in adults.

Modulation of the cGMP signaling pathway by melatonin in pancreatic beta-cells

Melatonin influences the second messenger cyclic guanosine 3',5'-monophosphate (cGMP) signaling pathway in pancreatic beta-cells via a receptor-mediated mechanism. In the present study, it was determined how the regulation of cGMP concentrations by melatonin proceeds. The results provide evidence that melatonin acts via the soluble guanylate cyclase (sGC), as molecular investigations demonstrated that long-term incubation with melatonin significantly reduced the expression levels of the sGC mRNA in rat insulinoma beta-cells (INS1) cells, whereas mRNA expression of membrane guanylate cyclases was unaffected. Incubation with melatonin abolished the S-nitrosoacetyl penicillamine-induced increase of cGMP concentrations in INS1 cells. In addition, the cGMP-inhibitory effect of melatonin was reversed by preincubation with the sGC inhibitors 1H-(1,2,4)oxadiazolo(4,3-alpha)quinoxalin-1-one and 4H-8-bromo-1,2,4-oxadiazolo(3,4-d)benz(b)(1,4)oxazin-1-one. Nitric oxide (NO) production was not influenced after 1 hr of melatonin application, but was influenced after a 4 hr incubation period. Preincubation of INS1 cells with the NO synthase inhibitor N(G)-monomethyl-l-arginine did not abolish the cGMP-inhibitory effect of melatonin. Transcripts of cyclic nucleotide-gated (CNG) channels were significantly reduced after melatonin treatment in a dose-dependent manner, indicating the involvement of these channels in mediating the melatonin effect in INS1 cells. The results of this study demonstrate that melatonin mediates its inhibitory effect on cGMP concentrations in pancreatic beta-cells by inhibiting the sGC, but does not influence NO concentration or NO synthase activity in short-term incubation experiments. In addition, it was demonstrated that melatonin is involved in modulation of CNG channel mRNA.

Ramelteon: new drug. Insomnia: no role for risky placebos

(1) Patients complaining of insomnia should first be treated with non-drug measures (information, advice). Short-course benzodiazepine therapy can be tried if non-drug measures and established herbal remedies fail; (2) Ramelteon, a drug that antagonises receptors for melatonin, a hormone involved in circadian rhythms, is being considered for European marketing authorization in the treatment of insomnia; (3) Ramelteon has only been compared with placebo in clinical trials. Only one of three trials in which the patients were studied in their normal environment showed that ramelteon reduced the time to sleep onset, only by about 10 minutes. A similar reduction was observed in the artificial conditions of a sleep laboratory. There was no effect on sleep duration or on the number of night-time awakenings; (4) Ramelteon does not appear to have the disadvantages of benzodiazepines, such as residual daytime drowsiness, rebound insomnia on drug withdrawal, and dependence. But ramelteon provokes hyperprolactinaemia and was carcinogenic in experimental animals; (5) In practice, when a drug is needed for a patient complaining of insomnia, the best options are phytotherapy or short-course benzodiazepine treatment.

[Melatoninergic receptor agonists and antagonists: therapeutic perspectives]

The chronobiotic neurohormone melatonin, synthetized in the pineal gland during darkness periods governs the circadian and seasonal biological rhythms. Physiologically, melatonin regulates the sleep/activity alternance, together with the circadian cycle of body temperature and cortisol secretion, and influences various immune, endocrine and metabolic functions. Dysfunction of the endogenous melatonin secretion is associated with mood and behavioral disorders including body weight. Patients with severe depression exhibit desynchronized and reduced melatonin secretion, in parallel with marked sleep disturbances whereas exogenous melatonin administration and antidepressive drugs restore melatonin secretion. A dysregulated melatonin secretion is also observed in obese subjects. Implication of melatonin in these disorders stimulated the search for melatonin analogues with enhanced antidepressive and body weight control effects. The melatoninergic agonist S 20098, or agomelatin, disclosed a potent antidepressive and anxiolytic activity in preclinical studies, which was confirmed in clinical trials in patients with major depression. The antagonist S 20928 was shown to limit seasonal weight gain in an hibernating rodent model. Thus, development of melatoninergic agonists and antagonists appear as an innovative approach in the treatment of depression and obesity, two major public health problems.

Patient-management strategies

An active cortex is necessary for intact cognitive function. In a sleepy individual, the cerebral cortex is to some extent deactivated; a sleep-deprived person will experience reduced physical and mental activity and productivity, more errors on the job, more risk for motor vehicle accidents, and psychosocial problems. Hormone levels can become imbalanced from excessive daytime sleepiness (EDS), and treatments for conditions unrelated to EDS can be hampered. Whether sleep restriction is voluntary or not, those who experience it habitually are at greater risk of obesity and type 2 diabetes. While an accurate history is necessary to diagnose sleep disorders, all too often a patient's chronic daytime sleepiness is never mentioned. EDS will not show up in most blood chemistries either. It is important that primary care providers ask patients about their sleep and its quality. Other screening tools include questionnaires, which are easily administered and can be sensitive. To determine the basis of EDS, formal sleep studies may be necessary.

Current landscape of insomnia in managed care

Insomnia affects a large percentage of the population, particularly the elderly. Literature reports varying estimates of prevalence, a variation that relates to the lack of definition and consistency in diagnostic criteria. Primary insomnia (not caused by known physical/mental conditions) responds to pharmacologic therapy, while secondary insomnia(resulting from other illnesses, medications, or sleep disorders) responds to pharmacologic and psychologic treatments (cognitive therapy, relaxation techniques, stimulus control). Use of certain agents in the elderly and patients with abuse/addiction potential is a concern. Medicare Part D does not cover benzodiazepines (classified as controlled substances). Nonprescription agents are affordable but have sedation and anticholinergic side effects. Medication use should be considered a possible contributing factor. Insomnia patients experience significantly more limited activity and higher total health services than those without insomnia. Annual costs are between $92.5 billion and $107.5 billion. A standard definition and better pathways to recognize and treat insomnia are needed.

Circadian rhythmicity and the pharmacologic management of insomnia

The circadian clock modulates timing of sleep and wakefulness. In certain situations, the circadian potentiation of wakefulness may interfere with desired sleep-scheduling, particularly in the elderly and shift workers. Known abnormalities of circadian regulation are defined by their impact on sleep-wake state expression. In delayed sleep phase syndrome, patients have trouble going to sleep and arising at reasonable hours and are alert in the evening and sleepy in the morning. Patients with advanced sleep phase syndrome are sleepy in the evening and awaken very early and alert in the morning. In shift-work sleep disorder, individuals attempt to wake and sleep out of phase with the circadian clock. As with jet lag, the clock is functioning normally, but the requirements on the clock are abnormal. Typical insomnia can also be associated with circadian rhythm alterations. Practice guidelines and clinical studies data are needed to lead appropriate therapy selection and effective management.

Efficacy of agomelatine, a MT1/MT2 receptor agonist with 5-HT2C antagonistic properties, in major depressive disorder

Current antidepressants used in major depressive disorder (MDD) are still not efficacious enough for many patients due to high levels of treatment resistance and bothersome side-effects. Using a novel blinding method (interactive voice response system), this flexible-dosing study examined the effects of therapeutic doses of agomelatine, a new approach to depressive therapy offering potent melatonergic MT1/MT2 receptor agonism with 5-HT2C receptor antagonist properties, in patients with moderate-to-severe MDD. This 6-wk, double-blind, parallel-group study randomized 238 patients to 25 mg/d agomelatine (with dose adjustment at 2 wk to 50 mg/d in patients with insufficient improvement) or placebo. Depression severity was assessed using the Hamilton Depression Rating Scale (HAMD) and the Clinical Global Impression (CGI) scale. Agomelatine was significantly more efficacious than placebo, with an agomelatine-placebo difference of 3.44 (p<0.001) using the HAMD final total score. Compared with placebo, agomelatine also had a significant positive impact on CGI - Improvement (treatment difference=0.45) and CGI - Severity (treatment difference=0.50) (both p=0.006), response rate (54.3% vs. 35.5% with placebo, p<0.05) and time to first response (p=0.008). Similar results were seen in patients with the most severe MDD. Depressed mood and sleep items of the HAMD were also significantly improved with agomelatine, which was well tolerated with a safety profile similar to placebo at both doses. This study confirms that agomelatine is effective in treating major depression, including the most severely depressed patients, with a good safety and tolerability profile, therefore providing physicians with an effective pharmacological approach to antidepressant therapy.

Management of comorbid insomnia

Many patients with primary medical or psychiatric disorders may be at risk for the development of comorbid insomnia. Research now suggests that effective treatment and management of the comorbid insomnia may be as important as the primary disorder--especially when the relationship between the two disorders is complex. Advanced practice nurses, in particular nurse practitioners and even professional nurses are well positioned by the nature of their educational preparation to assess for sleep disorders. Insomnia is an insidious illness. It deserves to be properly treated and every individual and patient, no matter their health state, deserves a good night's rest.