Differential effects of scopolamine on nocturnal cortisol secretion, sleep architecture, and REM latency in normal volunteers: relation to sleep and cortisol abnormalities in depression

Drug Design Targeting the Muscarinic Receptors and the Implications in Central Nervous System Disorders

There is substantial evidence that cholinergic system function impairment plays a significant role in many central nervous system (CNS) disorders. During the past three decades, muscarinic receptors (mAChRs) have been implicated in various pathologies and have been prominent targets of drug-design efforts. However, due to the high sequence homology of the orthosteric binding site, many drug candidates resulted in limited clinical success. Although several advances in treating peripheral pathologies have been achieved, targeting CNS pathologies remains challenging for researchers. Nevertheless, significant progress has been made in recent years to develop functionally selective orthosteric and allosteric ligands targeting the mAChRs with limited side effect profiles. This review highlights past efforts and focuses on recent advances in drug design targeting these receptors for Alzheimer’s disease (AD), schizophrenia (SZ), and depression.

FLT3 inhibitors in acute myeloid leukemia: ten frequently asked questions

The FMS-like tyrosine kinase 3 (FLT3) gene is mutated in approximately one third of patients with acute myeloid leukemia (AML), either by internal tandem duplications (FLT3-ITD), or by a point mutation mainly involving the tyrosine kinase domain (FLT3-TKD). Patients with FLT3-ITD have a high risk of relapse and low cure rates. Several FLT3 tyrosine kinase inhibitors have been developed in the last few years with variable kinase inhibitory properties, pharmacokinetics, and toxicity profiles. FLT3 inhibitors are divided into first generation multi-kinase inhibitors (such as sorafenib, lestaurtinib, midostaurin) and next generation inhibitors (such as quizartinib, crenolanib, gilteritinib) based on their potency and specificity of FLT3 inhibition. These diverse FLT3 inhibitors have been evaluated in myriad clinical trials as monotherapy or in combination with conventional chemotherapy or hypomethylating agents and in various settings, including front-line, relapsed or refractory disease, and maintenance therapy after consolidation chemotherapy or allogeneic stem cell transplantation. In this practical question-and-answer-based review, the main issues faced by the leukemia specialists on the use of FLT3 inhibitors in AML are addressed.

The Role of Muscarinic Receptors in the Pathophysiology of Mood Disorders: A Potential Novel Treatment?

The central cholinergic system has been implicated in the pathophysiology of mood disorders. An imbalance in central cholinergic neurotransmitter activity has been proposed to contribute to the manic and depressive episodes typical of these disorders. Neuropharmacological studies into the effects of cholinergic agonists and antagonists on mood state have provided considerable support for this hypothesis. Furthermore, recent clinical studies have shown that the pan-CHRM antagonist, scopolamine, produces rapid-acting antidepressant effects in individuals with either major depressive disorder (MDD) or bipolar disorder (BPD), such as bipolar depression, contrasting the delayed therapeutic response of conventional mood stabilisers and antidepressants. This review presents recent data from neuroimaging, post-mortem and genetic studies supporting the involvement of muscarinic cholinergic receptors (CHRMs), particularly CHRM2, in the pathophysiology of MDD and BPD. Thus, novel drugs that selectively target CHRMs with negligible effects in the peripheral nervous system might produce more rapid and robust clinical improvement in patients with BPD and MDD.

Randomised, double-blind study of the effects of oxybutynin, tolterodine, trospium chloride and placebo on sleep in healthy young volunteers

OBJECTIVE

Central nervous effects of oral anticholinergics may limit the success of incontinence therapy and patient compliance. Only a few studies investigating this topic are available. This study was conducted to determine whether oral anticholinergics alter sleep and psychometric test parameters.

DESIGN

Randomised, double-blind, crossover, placebo-controlled study.

STUDY PARTICIPANTS

24 healthy volunteers (age 22-36 years) without sleeprelated problems.

INTERVENTIONS

Polysomnographic recordings, sleep questionnaires and psychometric tests (the number combination test [Zahlen-Verbindungs Test; ZVT] and the d2 attention test) were performed following single doses of oxybutynin 15mg, tolterodine 4mg, trospium chloride 45mg or placebo, each separated by an 8-day washout period.

RESULTS

Rapid eye movement (REM) sleep (relative to total sleep time) was the primary parameter of polysomnography. The REM sleep for oxybutynin was significantly lower than that for trospium chloride (18.4% vs 20.2%; p < 0.05) and lower than that for placebo (20.1%; ns). The number combination test (ZVT), the primary parameter of cognitive function, and the d2 test did not reveal any differences in reaction time. With regard to the other sleep parameters, the REM latency for oxybutynin was clearly higher than that for placebo, trospium chloride and tolterodine. Effects on non-REM sleep were observed only after administration of oxybutynin compared with placebo.

CONCLUSIONS

Oxybutynin influenced sleep structure, as was reflected by REM suppression and mild sedation, while subjective parameters and psychometric tests remained unaffected. The sleep and psychometric test values for tolterodine and trospium chloride were comparable to those of placebo. The clinical relevance of these effects is small in healthy young volunteers, but these results cannot be extended to the elderly.

Electroencephalographic sleep and hypothalamic-pituitary-adrenal changes from episode to recovery in depressed adolescents

OBJECTIVE

The study examined electroencephalographic (EEG) sleep and hypothalamic-pituitary-adrenal (HPA) changes associated with depressive episode and during recovery in adolescent depression.

METHODS

Sixteen adolescents with major depressive disorder and 16 volunteers with no personal or family history of psychiatric disorder participated in a three-night EEG sleep protocol along with nocturnal urinary free cortisol (NUFC). Depressed subjects also were restudied during stable remission from the depressive episode.

RESULTS

Compared with controls, depressed adolescents had significantly reduced sleep efficiency, shorter latency to rapid eye movement (REM) sleep, increased phasic REM sleep, and elevated NUFC excretion. Among depressed subjects, EEG sleep values did not change significantly from episode to remission. NUFC excretion reduced significantly during remission from the depressive episode.

CONCLUSIONS

The findings that EEG sleep measures are independent of clinical state, whereas HPA variables are state dependent, suggest that sleep and HPA measures make a differential contribution to our understanding of the pathophysiology and prognosis of mood disorders in adolescent patients.

Effects on sleep of anticholinergics used for overactive bladder treatment in healthy volunteers aged > or = 50 years

OBJECTIVE

To study the influence of oxybutynin, tolterodine or trospium chloride, anticholinergics used to treat bladder overactivity, on sleep and the cognitive skills of healthy volunteers aged > or = 50 years.

SUBJECTS AND METHODS

In a randomized, double-blind, placebo-controlled study with a crossover design, 24 healthy sleepers (12 men and 12 women) aged 51-65 years underwent polysomnographic recordings and cognitive tests in a sleep laboratory. Study medications were given as a single dose containing the total recommended daily dose.

RESULTS

There was a significant reduction in rapid-eye movement (REM) sleep of approximately 15% and a slightly (but not significantly) greater REM latency after oxybutynin and tolterodine than with placebo. After trospium chloride, REM duration and latency were comparable with placebo. There was no effect of the tested anticholinergics on cognitive and subjective sleep variables.

CONCLUSION

Individuals aged > or = 50 years had a more distinct impairment of REM sleep after oxybutynin and tolterodine than had young people, but the reduction in REM sleep did not reach a pathological degree in this single-dose study. There was no apparent impairment of concentration or cognitive function, but impairment of cognitive function and neuropsychological side-effects cannot be excluded, especially when elderly patients with impaired REM sleep from various psychiatric diseases (e.g. depression) and/or sleep disturbances are given oxybutynin or tolterodine in long-term treatment.

REM sleep in depression is influenced by ethnicity

The influence of ethnicity on the manifestation of EEG sleep changes in depression was studied in 95 patients (21 African-Americans [AA], 17 Asians [AS], 37 Caucasians [C] and 20 Hispanics [H]) with unipolar major depression. Subjects were studied twice for 2 consecutive nights. On the second night of each 2-night session, placebo or scopolamine (1.5 microg/kg, IM, at 23.00 h) was administered. On the baseline (placebo) night, sleep architecture, sleep continuity and rapid eye movement (REM) sleep variables were generally comparable among the groups. However, REM sleep was less in AA and AS subjects than in C and H subjects. Furthermore, the distribution of REM sleep over the course of the night in AA and AS subjects differed significantly from that in the C and H groups. Although scopolamine significantly affected sleep continuity and REM sleep measures, no significant differential effects of scopolamine were observed. Because many antidepressants suppress REM sleep, the differences in baseline REM sleep observed might be related to the greater sensitivity of some ethnic-minority depressed patients to pharmacotherapy.

Relationship between ethnicity and sleep patterns in normal controls: implications for psychopathology and treatment

The purpose of the study was to examine ethnic influences on sleep regulation. Seventy-three normal volunteers from four ethnic groups (17 African-Americans, 10 Asians, 30 Caucasians and 16 Hispanics) were studied for two consecutive nights with sleep polysomnography recordings in the laboratory. The subjects were in good physical and psychological health, and were asymptomatic with respect to sleep/wake complaints or sleep disorders. With the exception of minor differences, sleep continuity, sleep architecture and rapid eye movement (REM) sleep patterns were comparable among the four groups. African-Americans had evidence of more stages 1 and 2 and diminished stage 4 sleep, whereas the Hispanics had higher REM density. These preliminary findings suggest that sleep patterns are remarkably similar across cultures. There are, however, important cross-ethnic differences, specifically in the depth of sleep and in phasic REM measures. Because sleep disturbances are common symptoms of emotional disorders and since many psychoactive agents affect sleep, cross-ethnic differences in sleep patterns may have potential implications for the treatment and prevention of psychiatric disorders.

Effects of drugs on sleep

Many commonly prescribed medications and substances of abuse can have significant effects on sleep and wakefulness. Chronic use or abuse of certain drugs may lead to the development of substance-related sleep disorders. Primary sleep disorders, such as apnea, periodic movement disorders, and parasomnias, may be exacerbated by various drugs. This article summarizes the effects of widely used medications and recreational drugs on sleep.

Sleep electroencephalographic abnormalities in adolescent depressives: effects of scopolamine

In contrast to sleep studies of adult depressives that have consistently demonstrated abnormalities of sleep continuity, slow-wave sleep, and REM sleep, existing studies of depressed children and adolescents have been conflicting. Furthermore, only one study has explored the cholinergic regulation of sleep in early-onset depressives. In the present study, the electroencephalographic sleep of 20 adolescent outpatients with major depressive episodes and 13 normal control adolescents was obtained on two separate 2-night sessions, 1 night incorporating challenge with scopolamine. Depressed adolescents showed increased baseline phasic REM sleep measures, increased arousals, a trend toward reduced slow-wave sleep, and a greater difference in the change of first REM period density on the scopolamine night versus placebo night compared to controls. These findings support the continuity of some sleep abnormalities of depression into adolescence, and suggest that adolescent depression may be associated with alterations of cholinergic neurotransmission in some patients.

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.

Effects of drugs on sleep

Many commonly prescribed medications and substances of abuse can have significant effects on sleep and wakefulness. Chronic use or abuse of certain drugs may lead to the development of substance-related sleep disorders. Primary sleep disorders, such as apnea, periodic movement disorders, and parasomnias, may be exacerbated by various drugs. This article summarizes the effects of widely used medications and recreational drugs on sleep.

Relationship between REM sleep latency and nocturnal cortisol concentrations in depressed patients

Due to conflicting reports on the possible association between shortening of rapid eye movement (REM) latency and increased cortisol secretion in patients with severe depression, this study examined the relationship between REM sleep latency and nocturnal cortisol concentration in 12 outpatients with major depression. The results showed a significant inverse correlation (r = -0.71, P < 0.01) between REM sleep latency and mean (23.00 hours-03.00 hours) plasma cortisol concentration. Age and severity of depression did not contribute to the inverse relationship. REM activity and density during the first REM period showed no significant correlations with the cortisol measures. A review of the literature suggests that this relationship might be unique to subjects with major depression, and again raises the possibility that these biological disruptions may have a common neurochemical basis.

The effects of scopolamine on sleep and mood in depressed patients with a history of alcoholism and a normal comparison group

In order to determine the effect of an anticholinergic agent on mood and sleep, scopolamine (0.4 mg IM) was administered before bedtime for three consecutive nights to 10 depressed patients (8 with a history of alcohol abuse) and 10 normal comparison subjects. The patients had a small, statistically significant antidepressant response on the second morning of treatment. Scopolamine inhibited rapid eye movement (REM) sleep and prolonged REM latency equally in depressed patients and the normal comparison group. Partial tolerance to the REM inhibiting effect of scopolamine developed between the first and third night of treatment. A REM rebound occurred during recovery nights. These results are consistent with concepts relating central cholinergic mechanisms to the control of REM sleep. Compared with controls, patients showed a greater increase in Stage 2 and Stage 2% and a lesser and increase in Delta (Stage 3 and 4) sleep % and Stage 4% on the first night of treatment. Further, well-controlled studies are needed to determine whether anticholinergic drugs possess clinically significant antidepressant effects.