The effects of REM sleep deprivation on striatal dopamine receptor sites

Circadian Rhythms in Mood Disorders

Altered behavioral rhythms are a fundamental diagnostic feature of mood disorders. Patients report worse subjective sleep and objective measures confirm this, implicating a role for circadian rhythm disruptions in mood disorder pathophysiology. Molecular clock gene mutations are associated with increased risk of mood disorder diagnosis and/or severity of symptoms, and mouse models of clock gene mutations have abnormal mood-related behaviors. The mechanism by which circadian rhythms contribute to mood disorders remains unknown, however, circadian rhythms regulate and are regulated by various biological systems that are abnormal in mood disorders and this interaction is theorized to be a key component of mood disorder pathophysiology. A growing body of evidence has begun defining how the interaction of circadian and neurotransmitter systems influences mood and behavior, including the role of current antidepressants and mood stabilizers. Additionally, the hypothalamus-pituitary-adrenal (HPA) axis interacts with both circadian and monoaminergic systems and may facilitate the contribution of environmental stressors to mood disorder pathophysiology. The central role of circadian rhythms in mood disorders has led to the development of chronotherapeutics, which are treatments designed specifically to target circadian rhythm regulators, such as sleep, light, and melatonin, to produce an antidepressant response.

Perspectives in affective disorders: Clocks and sleep

Mood disorders are often characterised by alterations in circadian rhythms, sleep disturbances and seasonal exacerbation. Conversely, chronobiological treatments utilise zeitgebers for circadian rhythms such as light to improve mood and stabilise sleep, and manipulations of sleep timing and duration as rapid antidepressant modalities. Although sleep deprivation ("wake therapy") can act within hours, and its mood-elevating effects be maintained by regular morning light administration/medication/earlier sleep, it has not entered the regular guidelines for treating affective disorders as a first-line treatment. The hindrances to using chronotherapeutics may lie in their lack of patentability, few sponsors to carry out large multi-centre trials, non-reimbursement by medical insurance and their perceived difficulty or exotic "alternative" nature. Future use can be promoted by new technology (single-sample phase measurements, phone apps, movement and sleep trackers) that provides ambulatory documentation over long periods and feedback to therapist and patient. Light combinations with cognitive behavioural therapy and sleep hygiene practice may speed up and also maintain response. The urgent need for new antidepressants should hopefully lead to reconsideration and implementation of these non-pharmacological methods, as well as further clinical trials. We review the putative neurochemical mechanisms underlying the antidepressant effect of sleep deprivation and light therapy, and current knowledge linking clocks and sleep with affective disorders: neurotransmitter switching, stress and cortico-limbic reactivity, clock genes, cortical neuroplasticity, connectomics and neuroinflammation. Despite the complexity of multi-system mechanisms, more insight will lead to fine tuning and better application of circadian and sleep-related treatments of depression.

Schizophrenia: the role of sleep and circadian rhythms in regulating dopamine and psychosis

Schizophrenia has long been associated with abnormalities in circadian rhythms and sleep. Up until now, there have been no thorough reviews of the potential mechanisms behind the myriad of circadian and sleep abnormalities observed in schizophrenia and psychosis. We present evidence of sleep playing an important role in psychosis predominantly mediated by dopaminergic pathways. A synthesis of both human and animal experimental work suggests that the interplay between sleep and dopamine is important in the generation and maintenance of psychosis. In particular, both animal and human data point to sleep disruption increasing dopamine release and sensitivity. Furthermore, elevated dopamine levels disrupt sleep and circadian rhythms. The synthesis of knowledge suggests that circadian rhythms, dopamine dysregulation, and psychosis are intricately linked. This suggests that treatment of circadian disturbance may be a useful target in improving the lives and symptoms of patients with schizophrenia.

Antidepressant chronotherapeutics for bipolar depression

Chronotherapeutics refers to treatments based on the principles of circadian rhythm organization and sleep physiology, which control the exposure to environmental stimuli that act on biological rhythms, in order to achieve therapeutic effects in the treatment of psychiatric conditions. It includes manipulations of the sleep-wake cycle such as sleep deprivation and sleep phase advance, and controlled exposure to light and dark. The antidepressant effects of chronotherapeutics are evident in difficult-to-treat conditions such as bipolar depression, which has been associated with extremely low success rates of antidepressant drugs in naturalistic settings and with stable antidepressant response to chronotherapeutics in more than half of the patients. Recent advances in the study of the effects of chronotherapeutics on neurotransmitter systems, and on the biological clock machinery, allow us to pinpoint its mechanism of action and to transform it from a neglected or “orphan” treatment to a powerful clinical instrument in everyday psychiatric practice.

Phase advance is an actimetric correlate of antidepressant response to sleep deprivation and light therapy in bipolar depression

The combination of total sleep deprivation (TSD) and light therapy (LT) in bipolar depression causes rapid antidepressant effects, and its mechanism of action has been hypothesized to involve the enhancement of all of the monoaminergic systems targeted by antidepressant drugs (serotonin, dopamine, norepinephrine). It is still unknown if the clinical effects are paralleled by changes in biological rhythms. In a before/after design of a study of biological correlates of response, 39 inpatients affected by Type I Bipolar Disorder whose current depressive episode was without psychotic features were treated for one week with repeated TSD combined with morning LT. Wrist actigraphy was recorded throughout the study. Two-thirds of the patients responded to treatment (50% reduction in Hamilton Depression score). Responders showed an increase in daytime activity, phase-advance of the activity-rest rhythm of 57 min compared to the pre-treatment baseline, and reduced nighttime sleep. Non-responders did not show significant changes in the parameters of their activity-rest rhythm. Phase advance of the activity-rest rhythm is an actimetric correlate of the antidepressant response to TSD and LT in bipolar depression. Results are consistent with the known effects of sleep-wake manipulations and neurotransmitter function on the suprachiasmatic nucleus.

Chronotherapeutics in a psychiatric ward

Psychiatric chronotherapeutics is the controlled exposure to environmental stimuli that act on biological rhythms in order to achieve therapeutic effects in the treatment of psychiatric conditions. In recent years some techniques (mainly light therapy and sleep deprivation) have passed the experimental developmental phase and reached the status of powerful and affordable clinical interventions for everyday clinical treatment of depressed patients. These techniques target the same brain neurotransmitter systems and the same brain areas as do antidepressant drugs, and should be administered under careful medical supervision. Their effects are rapid and transient, but can be stabilised by combining techniques among themselves or together with common drug treatments. Antidepressant chronotherapeutics target the broadly defined depressive syndrome, with response and relapse rates similar to those obtained with antidepressant drugs, and good results are obtained even in difficult-to-treat conditions such as bipolar depression. Chronotherapeutics offer a benign alternative to more radical treatments of depression for the treatment of severe depression in psychiatric wards, but with the advantage of rapidity of onset.

Clinical features of antidepressant associated manic and hypomanic switches in bipolar disorder

The present study investigated possible clinical differences between bipolar patients with and without manic or hypomanic switch during antidepressant (AD) treatment. The authors undertook a retrospective assessment of 169 individuals affected by bipolar disorder type I (BP I: n=96) and II (BP II: n=73) who experienced at least one manic or hypomanic episode following depression without any interposed normothymic period ("manic switch") during AD therapy. They were compared with a sex, age (+/-5 years), and ethnicity-matched group of 247 subjects, randomly selected from our pool of bipolar subjects who have never had manic switches. Only 2 of the 169 patients had had spontaneous switches before the AD-related one. Switched subjects were marginally older (t=-2.65, df=414, P=.008) compared to not switched and less frequently delusional (chi2=13.86, P=.0002). Polarity of the onset episode was more frequently depressive in switched patients (chi2=21.93, P=.00002), which had also less previous manic episodes than not switched (t=3.44, df=332, P=.0006). Those differences were more pronounced in the BP I subsample. Switched patients were more frequently BP I (chi2=29.66; P<.00001). Maintenance with mood stabilizers appears to be a strong protective factor; in fact, of the 124 individuals undertaking a mood stabilizer therapy, 21 had a switch and 103 had no switches (chi2=41.10, P<.000001). In conclusion, some clinical variables, such as the number of manic episodes, the presence of delusions, the polarity of onset episode, and the mood-stabilizing treatment, may be involved in AD-related switches. Further studies are required to investigate the causal relationships between those factors.

Dopamine receptor D4 is not associated with antidepressant activity of sleep deprivation

Total sleep deprivation (TSD) is an effective treatment for mood disorders which is thought to act through an enhancement in several neurotransmitter pathways including dopaminergic transmission. However, not all patients respond to TSD and genetic factors are likely to play a major role in determining TSD response. The aim of this study is to investigate the influence of dopamine receptor D4 exon 3 (DRD4) variants on TSD antidepressant efficacy in bipolar disorder. One hundred and twenty-four depressed inpatients affected by bipolar disorder (DSM-IV) were treated with repeated cycles of TSD and were typed for DRD4 variants at the third exon using polymerase chain reaction (PCR) techniques. DRD4 variants were not associated with TSD outcome. Consideration of possible stratification effects such as gender, age at onset and duration of illness did not reveal any association either. DRD4 exon 3 variants are not a main factor influencing TSD outcome in bipolar disorder.

The unipolar-bipolar dichotomy and the response to sleep deprivation

Fifty-one inpatients affected by a major depressive episode were divided into four groups according to mood disorder diagnosis and previous clinical history (bipolar disorder type I; bipolar disorder type II; major depressive disorder with at least three previous depressive episodes; and single depressive episode patients) and administered three consecutive total sleep deprivation (TSD) cycles. Mood changes were rated with a reduced version of the Hamilton Depression Rating Scale and with self-administered visual analogue scales. TSD caused better clinical effects in bipolar and single-episode patients; in particular, unipolar patients lacked effects in perceived mood after the first TSD and showed worse Hamilton ratings in respect to the other groups after the three TSD treatments. Discriminant function analysis could correctly classify 80% of bipolar patients, post hoc, based on TSD response. Further researches on the clinical efficacy of TSD must take into account the heterogeneity of depression and of its biological substrate.

Decreased activity of striatal monoamine oxidase B after rapid eye movement (REM) sleep deprivation in rats

The striatum seems to be the main brain region involved in stereotyped behavior induced by dopaminergic agonists. Rapid eye movement (REM) sleep deprivation increases dopaminergic agonist-induced stereotypy and produces biochemical changes in striatal dopaminergic neurotransmission. However, the mechanism underlying the increased dopaminergic sensitivity induced by REM sleep deprivation has not been elucidated. In an attempt to determine some of the biochemical changes in striatal dopaminergic neurotransmission that could contribute to REM sleep deprivation effects, we measured the activity of monoamine oxidase (MAO) A and B, the enzymes responsible for dopamine and beta-phenylethylamine (beta-PEA) deamination in striatum. Male adult rats were deprived of REM sleep for 96 h by the flower-pot technique. MAO A and B were assayed radioisotopically in the mitochondrial fraction by standard laboratory procedures, using [14C]-5-hydroxytryptamine (5-HT) and [14C]-beta-phenylethylamine (beta-PEA), as substrates for MAO A and MAO B, respectively. The results showed no significant statistical differences in striatal MAO A activity, whereas a significant decrease in MAO B activity was observed. The results are discussed in terms of the possible involvement of beta-PEA, a striatal endogenous trace amine, which potentiates dopaminergic neurotransmission and may participate in the increased dopaminergic sensitivity observed after REM sleep deprivation.

Effects of REM sleep deprivation on the d-amphetamine-induced self-mutilating behavior

It is well known that self-mutilating behavior (SMB) is developed in rats and humans during the daily treatment with d-amphetamine. Accordingly, in this work it was found that the daily treatment with 7.5 mg/kg d-amphetamine induced in rats a progressive appearance of SMB. Lower doses (5.0 mg/kg) were uneffective and higher doses (10 mg/kg) produced a pattern of SMB in which the mutilation induced at the beginning of the d-amphetamine administration disappears completely as the treatment progresses. Interestingly, it was also found that REM sleep deprivation (48 h) potentiated significantly the SMB induced by the daily administration of 7.5 mg/kg d-amphetamine, and to lesser extent, the SMB induced by the daily treatment with 10 mg/kg d-amphetamine. R(+)-SCH-23390 a D1 dopamine (DA) receptor antagonist blocked completely or abolished the SMB induced by 7.5 mg/kg d-amphetamine in REM sleep deprived rats while (+/-)-sulpiride a D2 DA receptor antagonist had only a partial blocking effect. Haloperidol a D1/D2 DA receptor antagonist behaved as a D1 antagonist. Our results indicate that REM sleep deprivation enhances the SMB induced by the daily administration of d-amphetamine and suggest the involvement of D1 DA receptors in the mechanism underlying the SMB. A role of REM sleep deprivation is also suggested in the appearance of self-mutilating episodes in d-amphetamine addicts.

Rapid eye movement (REM) sleep deprivation reduces rat frontal cortex acetylcholinesterase (EC 3.1.1.7) activity

Rapid eye movement (REM) sleep deprivation induces several behavioral changes. Among these, a decrease in yawning behavior produced by low doses of cholinergic agonists is observed which indicates a change in brain cholinergic neurotransmission after REM sleep deprivation. Acetylcholinesterase (Achase) controls acetylcholine (Ach) availability in the synaptic cleft. Therefore, altered Achase activity may lead to a change in Ach availability at the receptor level which, in turn, may result in modification of cholinergic neurotransmission. To determine if REM sleep deprivation would change the activity of Achase, male Wistar rats, 3 months old, weighing 250-300 g, were deprived of REM sleep for 96 h by the flower-pot technique (N = 12). Two additional groups, a home-cage control (N = 6) and a large platform control (N = 6), were also used. Achase was measured in the frontal cortex using two different methods to obtain the enzyme activity. One method consisted of the obtention of total (900 g supernatant), membrane-bound (100,000 g pellet) and soluble (100,000 g supernatant) Achase, and the other method consisted of the obtention of a fraction (40,000 g pellet) enriched in synaptic membrane-bound enzyme. In both preparations, REM sleep deprivation induced a significant decrease in rat frontal cortex Achase activity when compared to both home-cage and large platform controls. REM sleep deprivation induced a significant decrease of 16% in the membrane-bound Achase activity (nmol thiocholine formed min-1 mg protein-1) in the 100,000 g pellet enzyme preparation (home-cage group 152.1 +/- 5.7, large platform group 152.7 +/- 24.9 and REM sleep-deprived group 127.9 +/- 13.8). There was no difference in the soluble enzyme activity. REM sleep deprivation also induced a significant decrease of 20% in the enriched synaptic membrane-bound Achase activity (home-cage group 126.4 +/- 21.5, large platform group 127.8 +/- 20.4, REM sleep-deprived group 102.8 +/- 14.2). Our results suggest that REM sleep deprivation changes Ach availability at the level of its receptors through a decrease in Achase activity.

Differential role of dopamine receptors on motor asymmetries of nigro-striatal lesioned animals that are REM sleep deprived

Recently, we have shown that rapid eye movement sleep deprivation (REM-SD) in animals with lesions of the nigro-striatal pathway facilitates turning behavior and such increase still occurred even in the presence of dopaminergic grafts. The objective of this work was to determine which DA receptors are preferentially involved. The results showed that the D2 receptor antagonist sulpiride decreases significantly turning behavior of lesioned animals, with no effect whatsoever of the D1 antagonist SCH 23390. When lesioned animals were REM sleep deprived, the D1 but not the D2 receptor antagonist prevented the increase of turning induced by REM-SD. This work suggests that the increase of post-synaptic supersensitivity induced by REM-SD in nigro-striatal lesioned animals is mediated by D1 receptors.

Sleep deprivation hastens the antidepressant action of fluoxetine

Among ten bipolar depressed patients admitted to our psychiatric ward, five patients were treated with fluoxetine alone and five subjects were treated with fluoxetine in association with total sleep deprivation (TSD) in order to evaluate the effect of the interaction between the administration of the serotonergic antidepressant compound fluoxetine and repeated cycles of TSD. Patients treated with fluoxetine plus repeated TSD showed a faster amelioration of depressive symptomatology compared with the other group. We discuss our findings hypothesizing an enhancement in dopaminergic and possibly in serotonergic transmission due to repeated TSD adding to the increase in serotonergic transmission due to fluoxetine medication.

Dopamine agonist amineptine prevents the antidepressant effect of sleep deprivation

In a double-blind study, the effects of the interaction between the administration of amineptine versus placebo and repeated cycles of total sleep deprivation (TSD), which is thought to act through an enhancement in dopaminergic transmission, were analyzed. Twenty-two consecutively admitted patients with bipolar depression formed the study group. Repeated administrations of TSD significantly enhanced perceived mood levels in placebo-treated patients, while amineptine administration blocked the antidepressant action of TSD. Hypothesized changes in brain dopaminergic transmission attributable to amineptine pretreatment are discussed.

Single photon emission computerized tomography assessment of cerebral dopamine D2 receptor blockade in depression before and after sleep deprivation--preliminary results

The antidepressant properties of total sleep deprivation (TSD) have been well established. There is some evidence that TSD may improve depression by altering central dopamine (DA) function. We therefore studied five depressed TSD responders and five TSD nonresponders after sleep and after TSD and five controls after sleep with IBZM single photon emission computerized tomography (SPECT). Responders showed a significant decrease (Wilcoxon--test p < 0.05) of relative basal ganglia D2 receptor occupancy after TSD compared to nonresponders (change score responders versus nonresponders p < 0.05, U-test). The data are interpreted as a sign of an enhanced DA release in responders. The results confirm previous hypotheses of dopaminergic involvement in the therapeutic action of TSD and indirectly support a dopamine hypotheses of depression.

Effects of rapid eye movement sleep deprivation on the properties of striatal dopaminergic system

Using the water tank procedure, we have examined the effects of rapid eye movement (REM) sleep deprivation and associated stress on the properties of striatal dopaminergic system. While stress decreased the number of D1 and D2 dopamine receptors, a combination of REM sleep deprivation attenuated the decrease. The ratio of D1 to D2 densities, however, increased on both the stress and REM sleep deprivation groups. In contrast, the number of dopamine uptake sites remained unchanged. The enhanced behavioral responses to dopaminergic stimulants after REM sleep deprivation are discussed.

Potentiation of metaphit-induced audiogenic seizures by REM sleep deprivation in rats

The possibility that REM sleep deprivation (REMD) induced increased susceptibility of rats to the convulsive effects of metaphit was investigated. Metaphit-induced audiogenic seizures were studied in three groups of animals: 1) caged controls; 2) large platform animals; and 3) small platform, REMD animals. After 48 h of confinement to their environments the rats from all three groups were injected with metaphit (10 mg kg-1, IP) and the procedures continued for the next 24 h. Immediately after removal from platforms and at 3-h intervals thereafter all rats were individually subjected to intense sound stimulation. Convulsive responses were recorded and analyzed with respect to incidence, intensity, and duration. The REMD rats were found to be more sensitive to the convulsive effects of metaphit compared to nondeprived rats. This was manifested in significantly shorter latencies to seizures, and significantly higher incidence, severity, and duration of seizures, especially of the most severe seizure component-tonic extensor convulsion. Inducing rats to convulse while they were being REM sleep deprived eliminated the REM sleep rebound observed in REMD rats that did not convulse. The occurrence of spontaneous EEG seizures during the undisturbed recovery period reduced REM sleep rebound. The results demonstrate a reciprocal relation between seizure behavior and REM sleep.

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)

Changes in 24-hour urinary excretion of MHPG after four continuous nights of REM sleep deprivation in human volunteers

Eight healthy volunteers were deprived of rapid eye movement (REM) sleep for 4 consecutive nights. Twenty-four-hour urine samples were collected to determine levels of 3-methoxy-4-hydroxyphenylglycol (MHPG) during basal, REM sleep deprivation, and REM recovery conditions. A control experiment was carried out in four subjects who were awakened in non-REM sleep for 4 consecutive nights. Subjects deprived of REM sleep showed significant MHPG increases on night 4 of sleep deprivation. MHPG levels in the control condition decreased, but not significantly. When MHPG levels in both experimental and control conditions were compared in the same four subjects, a significant difference was observed, indicating an effect of the control condition. Increased MHPG levels were related to REM sleep reduction and to the time and number of awakenings. Our findings seem to support an inverse homeostatic relationship between norepinephrine metabolism and REM sleep.

Central responses to cholinergic drugs of REM sleep deprived rats

The present work studied the effects of REM sleep deprivation on the responses to cholinomimetic drugs in rats. Cataleptic behavior induced by pilocarpine, oxotremorine and eserine was not modified by previous REM sleep deprivation. On the other hand, the intensity of oxotremorine- and eserine-induced tremors, but not that of pilocarpine, was clearly augmented in the REMd rats and latency to the first tremor was shorter. REM sleep deprivation also potentiated the convulsions induced by nicotine. Two hypothetical mechanisms through which REM sleep deprivation could lead to the described hyperresponsiveness to cholinomimetic drugs are discussed.

Apomorphine in the evaluation of dopaminergic function in man

1. Apomorphine (Apo), a short acting dopamine (DA) receptor agonist, stimulates growth hormone (GH) secretion, decreases prolactin secretion, induces yawning, penile erections and other physiological effects in man. An effect on behavior, movement disorders and alcoholism has also been described. 2. Apo-mediated responses are used to evaluate DA function in psychiatric and neurological disorders. Many of the studies in schizophrenia using the GH response to Apo as an index of central DA function are difficult to interpret because of failure to control for key variables. 3. The GH response to Apo is a useful system to evaluate the effects of various drugs including peptides which may not cross the blood brain barrier on DA function in man. 4. Apo is a potent sedative. Specific antimanic, antischizophrenic, and anticraving effects in alcoholics have not been convincingly demonstrated. Side effects of Apo and failure to use active placebo make double-blind studies difficult. 5. Apo improves parkinsonian symptoms and certain forms of reflex epilepsy but beneficial effects in other involuntary movement disorders requires further documentation. 6. Apo may be a useful agent to evaluate DA function in impotent patients and predict a therapeutic response to long-acting dopaminergic agents. 7. Impairment of DA function may play a role in diabetic impotence. 8. The development of a simple polygraphic method to monitor the yawning response to Apo may facilitate clinical studies on the basic physiology of yawning in man and the use of the yawning response as a measure of central DA function in schizophrenia and other clinical disorders. 9. The use of Apo with 18F-fluorodeoxyglucose positron emission tomography to examine regional DA function in man opens up a promising area of research. 10. Though long-acting orally active aporphine DA agonists and antagonists have been developed the problem of tolerance may limit their therapeutic potential.