Cell-type-specific representation of spatial context in the rat prefrontal cortex.

The ability to represent one's own position in relation to cues, goals, or threats is crucial to successful goal-directed behavior. Using optotagging in knock-in rats expressing Cre recombinase in parvalbumin (PV) neurons (PV-Cre rats), we demonstrate cell-type-specific encoding of spatial and movement variables in the medial prefrontal cortex (mPFC) during goal-directed reward seeking. Single neurons encoded the conjunction of the animal's spatial position and the run direction, referred to as the spatial context. The spatial context was most prominently represented by the inhibitory PV interneurons. Movement toward the reward was signified by increased local field potential (LFP) oscillations in the gamma band but this LFP signature was not related to the spatial information in the neuronal firing. The results highlight how spatial information is incorporated into cognitive operations in the mPFC. The presented PV-Cre line opens the door for expanded research approaches in rats.

Safety and efficacy of once-daily dexfadrostat phosphate in patients with primary aldosteronism: a randomised, parallel group, multicentre, phase 2 trial.

Background: Primary aldosteronism (PA) is caused by autonomous aldosterone overproduction and characterised by uncontrolled hypertension. There are currently no treatments that target aldosterone synthesis. We evaluated the safety and efficacy of a novel aldosterone synthase inhibitor, dexfadrostat phosphate, in patients with PA. Methods: This multi-centre, randomised, phase 2 trial was conducted between November 2019 and May 2022 (NCT04007406; EudraCT code 2019-000919-85). Adults with PA and an office systolic blood pressure of 145-190 mmHg were included. After a 2-week single-blind placebo run-in period, participants were randomised 1:1:1 to receive oral dexfadrostat phosphate 4, 8, or 12 mg once daily for an 8-week double-blind treatment period, followed by a 2-week single-blind placebo withdrawal period. Randomisation was conducted centrally and stratified by centre and sex. At the beginning and end of the treatment period, 24 h ambulatory systolic blood pressure (aSBP) was recorded. Blood samples were taken every 2 weeks. Primary endpoints were the change in aldosterone-to-renin ratio (ARR) and mean 24 h aSBP from baseline to the end of the treatment period in the combined dose group of all participants receiving any dose of dexfadrostat phosphate. Safety endpoints were the occurrence of treatment-emergent adverse events (TEAEs) and serious adverse events over the entire study in all randomised participants who received at least one dose of dexfadrostat phosphate. Findings: In total, 35 participants received dexfadrostat phosphate and all participants completed the study. Twenty-six participants (74.3%) were male, the mean age was 51.9 years (SD 8.7), and most were White (n = 32, 91.4%). The median ARR and the mean 24 h aSBP significantly decreased from the beginning to the end of the treatment period in the combined dose group (ARR: 15.3 vs 0.6, least-squares mean [LSM] change in log-normal values -2.5, p < 0.0001; aSBP: 142.6 vs 131.9 mmHg, LSM change -10.7 mmHg, p < 0.0001). There were no safety concerns; all TEAEs were mild or moderate and there were no serious TEAEs. Interpretation: Dexfadrostat phosphate corrected the ARR and aSBP and was well tolerated in patients with PA, demonstrating the benefit of pharmacologically targeting the source of hyperaldosteronism. Funding: DAMIAN Pharma AG.

Linking QKD Testbeds across Europe.

Quantum-key-distribution (QKD) networks are gaining importance and it has become necessary to analyze the most appropriate methods for their long-distance interconnection. In this paper, four different methods of interconnecting remote QKD networks are proposed. The methods are used to link three different QKD testbeds in Europe, located in Berlin, Madrid, and Poznan. Although long-distance QKD links are only emulated, the methods used can serve as a blueprint for the secure interconnection of distant QKD networks in the future. Specifically, the presented approaches combine, in a transparent way, different fiber and satellite physical media, as well as common standards of key delivery interfaces. The testbed interconnections are designed to increase the security by utilizing multipath techniques and multiple hybridizations of QKD and post-quantum cryptography (PQC) algorithms.

Robotic arm training in neurorehabilitation enhanced by augmented reality - a usability and feasibility study.

BACKGROUND: Robotic therapy and serious gaming support motor learning in neurorehabilitation. Traditional monitor-based gaming outputs cannot adequately represent the third dimension, whereas virtual reality headsets lack the connection to the real world. The use of Augmented Reality (AR) techniques could potentially overcome these issues. The objective of this study was thus to evaluate the usability, feasibility and functionality of a novel arm rehabilitation device for neurorehabilitation (RobExReha system) based on a robotic arm (LBR iiwa, KUKA AG) and serious gaming using the AR headset HoloLens (Microsoft Inc.). METHODS: The RobExReha system was tested with eleven adult inpatients (mean age: 64.4 ± 11.2 years; diagnoses: 8 stroke, 2 spinal cord injury, 1 Guillain-Barré-Syndrome) who had paretic impairments in their upper limb. Five therapists administered and evaluated the system. Data was compared with a Reference Group (eleven inpatients; mean age: 64.3 ± 9.1 years; diagnoses: 10 stroke, 1 spinal cord injury) who trained with commercially available robotic therapy devices (ArmeoPower or ArmeoSpring, Hocoma AG). Patients used standardized questionnaires for evaluating usability and comfort (Quebec User Evaluation of Satisfaction with assistive technology [QUEST]), workload (Raw Task Load Index [RTLX]) and a questionnaire for rating visual perception of the gaming scenario. Therapists used the QUEST, the System Usability Scale and the short version of the User Experience Questionnaire. RESULTS: Therapy with the RobExReha system was safe and feasible for patients and therapists, with no serious adverse events being reported. Patients and therapists were generally satisfied with usability. The patients' usability ratings were significantly higher in the Reference Group for two items of the QUEST: reliability and ease of use. Workload (RTLX) ratings did not differ significantly between the groups. Nearly all patients using the RobExReha system perceived the gaming scenario in AR as functioning adequately despite eight patients having impairments in stereoscopic vision. The therapists valued the system's approach as interesting and inventive. CONCLUSIONS: We demonstrated the clinical feasibility of combining a novel robotic upper limb robot with an AR-serious game in a neurorehabilitation setting. To ensure high usability in future applications, a reliable and easy-to-use system that can be used for task-oriented training should be implemented. TRIAL REGISTRATION: Ethical approval was obtained and the trial was registered at the German Clinical Trials Register (DRKS00022136).

CYP11B2 inhibitor dexfadrostat phosphate suppresses the aldosterone-to-renin ratio, an indicator of sodium retention, in healthy volunteers.

AIMS: High aldosterone is a key driver of hypertension and long-term negative sequelae. We evaluated the safety and efficacy of dexfadrostat phosphate (DP13), a novel aldosterone synthase (CYP11B2) inhibitor, in healthy participants. METHODS: This randomized, double-blind, placebo-controlled study was conducted in two parts. In part A, a single-ascending dose escalation, 16 participants received oral DP13 1-16 mg. Part B was a multiple-ascending dose, sequential group study in which 32 participants received oral DP13 4, 8 or 16 mg once daily for 8 days. Safety and tolerability were monitored throughout. An adrenocorticotropic hormone (ACTH) stimulation test at maximal blood drug concentrations defined the dose range for multiple dosing. RESULTS: DP13 was well tolerated at all doses, with no serious adverse events. In part B, all DP13 doses (4, 8 and 16 mg) over 8 days effectively suppressed aldosterone production, increased the urinary sodium/potassium ratio, decreased plasma sodium and increased plasma potassium and renin levels compared with placebo, resulting in potent suppression of the aldosterone-to-renin ratio (ARR). Endocrine counter-regulation resulted in the 4 mg dose no longer sustaining 24-h aldosterone suppression after 8 days of treatment, unlike the 8- and 16 mg doses. There was no evidence of drug-induced adrenal insufficiency (ACTH stress challenge). CONCLUSIONS: In patients with excess aldosterone and ensuing sodium retention driving hypertension, managing sodium balance is critical. A CYP11B2 inhibitor like DP13, whose effectiveness can be monitored by a reduction in ARR, may prove valuable in managing aldosterone-dependent hypertension and primary aldosteronism.

The DMCdrive: practical 3D-printable micro-drive system for reliable chronic multi-tetrode recording and optogenetic application in freely behaving rodents.

Electrophysiological recording and optogenetic control of neuronal activity in behaving animals have been integral to the elucidation of how neurons and circuits modulate network activity in the encoding and causation of behavior. However, most current electrophysiological methods require substantial economical investments and prior expertise. Further, the inclusion of optogenetics with electrophysiological recordings in freely moving animals adds complexity to the experimental design. Expansion of the technological repertoire across laboratories, research institutes, and countries, demands open access to high-quality devices that can be built with little prior expertise from easily accessible parts of low cost. We here present an affordable, truly easy-to-assemble micro-drive for electrophysiology in combination with optogenetics in freely moving rodents. The DMCdrive is particularly suited for reliable recordings of neurons and network activities over the course of weeks, and simplify optical tagging and manipulation of neurons in the recorded brain region. The highly functional and practical drive design has been optimized for accurate tetrode movement in brain tissue, and remarkably reduced build time. We provide a complete overview of the drive design, its assembly and use, and proof-of-principle demonstration of recordings paired with cell-type-specific optogenetic manipulations in the prefrontal cortex (PFC) of freely moving transgenic mice and rats.

Quantitative Gd-DOTA uptake from cerebrospinal fluid into rat brain using 3D VFA-SPGR at 9.4T.

PURPOSE: We propose a quantitative technique to assess solute uptake into the brain parenchyma based on dynamic contrast-enhanced MRI (DCE-MRI). With this approach, a small molecular weight paramagnetic contrast agent (Gd-DOTA) is infused in the cerebral spinal fluid (CSF) and whole brain gadolinium concentration maps are derived. METHODS: We implemented a 3D variable flip angle spoiled gradient echo (VFA-SPGR) longitudinal relaxation time (T1) technique, the accuracy of which was cross-validated by way of inversion recovery rapid acquisition with relaxation enhancement (IR-RARE) using phantoms. Normal Wistar rats underwent Gd-DOTA infusion into CSF via the cisterna magna and continuous MRI for approximately 130 min using T1-weighted imaging. Dynamic Gd-DOTA concentration maps were calculated and parenchymal uptake was estimated. RESULTS: In the phantom study, T1 discrepancies between the VFA-SPGR and IR-RARE sequences were approximately 6% with a transmit coil inhomogeneity correction. In the in vivo study, contrast transport profiles indicated maximal parenchymal retention of approximately 19% relative to the total amount delivered into the cisterna magna. CONCLUSION: Imaging strategies for accurate 3D contrast concentration mapping at 9.4T were developed and whole brain dynamic concentration maps were derived to study solute transport via the glymphatic system. The newly developed approach will enable future quantitative studies of the glymphatic system in health and disease states. Magn Reson Med 79:1568-1578, 2018. © 2017 International Society for Magnetic Resonance in Medicine.

Does Size Really Matter? The Role of Tonotopic Map Area Dynamics for Sound Learning in Mouse Auditory Cortex.

This commentary centers on the novel findings by Shepard et al. (2016) published in eNeuro. The authors interrogated tonotopic map dynamics in auditory cortex (ACtx) by employing a natural sound-learning paradigm, where mothers learn the importance of pup ultrasonic vocalizations (USVs), allowing Shepard et al. to probe the role of map area expansion for auditory learning. They demonstrate that auditory learning in this paradigm does not rely on map expansion but is facilitated by increased inhibition of neurons tuned to low-frequency sounds. Here, we discuss the findings in light of the emerging enthusiasm for cortical inhibitory interneurons for circuit function and hypothesize how a particular interneuron type might be causally involved for the intriguing results obtained by Shepard et al.

Angiotensin II type 1 receptor antagonists in animal models of vascular, cardiac, metabolic and renal disease.

We have reviewed the effects of angiotensin II type 1 receptor antagonists (ARBs) in various animal models of hypertension, atherosclerosis, cardiac function, hypertrophy and fibrosis, glucose and lipid metabolism, and renal function and morphology. Those of azilsartan and telmisartan have been included comprehensively whereas those of other ARBs have been included systematically but without intention of completeness. ARBs as a class lower blood pressure in established hypertension and prevent hypertension development in all applicable animal models except those with a markedly suppressed renin-angiotensin system; blood pressure lowering even persists for a considerable time after discontinuation of treatment. This translates into a reduced mortality, particularly in models exhibiting marked hypertension. The retrieved data on vascular, cardiac and renal function and morphology as well as on glucose and lipid metabolism are discussed to address three main questions: 1. Can ARB effects on blood vessels, heart, kidney and metabolic function be explained by blood pressure lowering alone or are they additionally directly related to blockade of the renin-angiotensin system? 2. Are they shared by other inhibitors of the renin-angiotensin system, e.g. angiotensin converting enzyme inhibitors? 3. Are some effects specific for one or more compounds within the ARB class? Taken together these data profile ARBs as a drug class with unique properties that have beneficial effects far beyond those on blood pressure reduction and, in some cases distinct from those of angiotensin converting enzyme inhibitors. The clinical relevance of angiotensin receptor-independent effects of some ARBs remains to be determined.

Aldosterone synthase inhibition for the treatment of hypertension and the derived mechanistic requirements for a new therapeutic strategy.

CONTEXT: We describe the clinical investigation of the first generation aldosterone synthase inhibitor, LCI699, in patients with essential, uncontrolled, resistant, or secondary hypertension. LCI699 competitively reduced blood pressure at lower doses yet counterintuitive effects were observed at higher doses. OBJECTIVE AND METHOD: An extensive endocrine biomarker analysis was performed to better understand the pharmacological mechanism of the drug. RESULTS: The interference of LCI699 in the renin-angiotensin-aldosterone system occurred with limited target selectivity, as a dose-dependent compensatory stimulation of the hypothalamic-pituitary-adrenal feedback axis was discovered. Thus, LCI699 affected two endocrine feedback loops that converged at a single point, inhibiting the 11ß-hydroxylase reaction in the adrenal gland, leading to supraphysiological levels of 11-deoxycortiscosterone. The accumulation of this potent mineralocorticoid may explain the blunted blood pressure response to LCI699. CONCLUSION: Future aldosterone synthase inhibitors may improve their target selectivity by sparing the 11ß-hydroxylase reaction and preferentially inhibiting one of the two other enzymatic reactions mediated by aldosterone synthase.

A systematic comparison of the properties of clinically used angiotensin II type 1 receptor antagonists.

Angiotensin II type 1 receptor antagonists (ARBs) have become an important drug class in the treatment of hypertension and heart failure and the protection from diabetic nephropathy. Eight ARBs are clinically available [azilsartan, candesartan, eprosartan, irbesartan, losartan, olmesartan, telmisartan, valsartan]. Azilsartan (in some countries), candesartan, and olmesartan are orally administered as prodrugs, whereas the blocking action of some is mediated through active metabolites. On the basis of their chemical structures, ARBs use different binding pockets in the receptor, which are associated with differences in dissociation times and, in most cases, apparently insurmountable antagonism. The physicochemical differences between ARBs also manifest in different tissue penetration, including passage through the blood-brain barrier. Differences in binding mode and tissue penetration are also associated with differences in pharmacokinetic profile, particularly duration of action. Although generally highly specific for angiotensin II type 1 receptors, some ARBs, particularly telmisartan, are partial agonists at peroxisome proliferator-activated receptor-γ. All of these properties are comprehensively reviewed in this article. Although there is general consensus that a continuous receptor blockade over a 24-hour period is desirable, the clinical relevance of other pharmacological differences between individual ARBs remains to be assessed.

Cardiovascular outcomes in hypertensive patients: comparing single-agent therapy with combination therapy.

OBJECTIVES: To determine whether blood pressure (BP) control in hypertensive patients achieved with combination drug therapy provides the same cardiovascular benefits as with single-agent therapy. BACKGROUND: Drug combinations, most often including hydrochlorothiazide (HCTZ), are now recommended for routine BP management, but their effects on cardiovascular event rates have not been compared with effective monotherapy. METHODS: We conducted retrospective analyses of the Valsartan Antihypertensive Long-term Use Evaluation (VALUE) data. VALUE compared cardiovascular event rates of valsartan and amlodipine. Patients with BPs not controlled (<140/90  mmHg) by the single agents had HCTZ and, if required, additional drugs of different classes, added. Using data pooled from the two treatment arms, we have now divided patients into those controlled on monotherapy and those controlled or not controlled by combination therapy. The primary study endpoint was first occurrence of cardiovascular death or nonfatal myocardial infarction or stroke. Comparisons between groups were by Cox regression, adjusted for on-treatment BP, age, prior cardiovascular events and left ventricular hypertrophy; the comparison between the monotherapy and combination therapy controlled groups was based on events occurring after 3 months by when the decision to use monotherapy or combination therapy was made. RESULTS: The primary endpoint occurred in 505 of 5924 (8.5%) monotherapy and 511 of 4621 (11.1%) combination therapy controlled patients: hazard ratio was 0.80 [95% confidence interval (CI) 0.70-0.90]. If these two groups were matched for baseline BPs and all events included from study baseline, the hazard ratio was 0.76 (95% CI 0.67-0.86). The difference between combination controlled and uncontrolled [434 of 3390 (12.8%)] groups was not significant [hazard ratio 0.90 (95% CI 0.80-1.03], nor when they were matched for baseline BPs [hazard ratio 0.95 (95% CI 0.81-1.11)]. CONCLUSION: Independent of prior cardiovascular history or baseline BP, hypertensive patients requiring combination therapy, which includes a thiazide diuretic for BP control, have a poorer cardiovascular prognosis than those controlled by monotherapy and only a nonsignificantly lower event rate than noncontrolled patients.

Usefulness of heart rate to predict cardiac events in treated patients with high-risk systemic hypertension.

A high heart rate (HR) predicts future cardiovascular events. We explored the predictive value of HR in patients with high-risk hypertension and examined whether blood pressure reduction modifies this association. The participants were 15,193 patients with hypertension enrolled in the Valsartan Antihypertensive Long-term Use Evaluation (VALUE) trial and followed up for 5 years. The HR was assessed from electrocardiographic recordings obtained annually throughout the study period. The primary end point was the interval to cardiac events. After adjustment for confounders, the hazard ratio of the composite cardiac primary end point for a 10-beats/min of the baseline HR increment was 1.16 (95% confidence interval 1.12 to 1.20). Compared to the lowest HR quintile, the adjusted hazard ratio in the highest quintile was 1.73 (95% confidence interval 1.46 to 2.04). Compared to the pooled lower quintiles of baseline HR, the annual incidence of primary end point in the top baseline quintile was greater in each of the 5 study years (all p <0.05). The adjusted hazard ratio for the primary end point in the highest in-trial HR heart rate quintile versus the lowest quintile was 1.53 (95% confidence interval 1.26 to 1.85). The incidence of primary end points in the highest in-trial HR group compared to the pooled 4 lower quintiles was 53% greater in patients with well-controlled blood pressure (p <0.001) and 34% greater in those with uncontrolled blood pressure (p = 0.002). In conclusion, an increased HR is a long-term predictor of cardiovascular events in patients with high-risk hypertension. This effect was not modified by good blood pressure control. It is not yet known whether a therapeutic reduction of HR would improve cardiovascular prognosis.

Practical solutions to the challenges of uncontrolled hypertension: a white paper.

This white paper is an urgent call to action from an international group of physicians. The continued failure to control hypertension takes an unacceptable toll on patients, families and society and it must be addressed. Any patient with blood pressure of 140/90 mmHg or greater can be characterized as a 'challenging patient', is at significant risk, and requires persistent optimization of therapy until target blood pressure is achieved. Six key challenges in reaching this goal blood pressure are described: (1) inadequate primary prevention; (2) faulty awareness of risk; (3) lack of simplicity; (4) therapeutic inertia; (5) insufficient patient empowerment; and (6) unsupportive healthcare systems. This white paper identifies straightforward actions that will produce rapid improvements in the management of hypertension, with a simple aim: to treat all challenging patients effectively to goal blood pressure, preventing disability and saving lives.

Under pressure: future prospects in hypertension management. Interview by Laura Dormer.

Professor Hans Rudolf Brunner Born in 1937, Professor Brunner is a Swiss citizen. He is a Professor Emeritus of Medicine at the University of Lausanne, Switzerland. He has been at the forefront of research on the role of renin and the renin-angiotensin system in blood pressure regulation. He has been involved in the development of drugs such as angiotensin-converting enzyme inhibitors and angiotensin receptor blockers. He was among the first medical practitioners to introduce the use of angiotensin-converting enzyme inhibitors in the treatment of hypertension and congestive heart failure. Professor Brunner has been a medical advisor to Speedel since 1999.

The Munich vulnerability study on affective disorders: microstructure of sleep in high-risk subjects.

Vulnerability markers for affective disorders have focused on stress hormone regulation and sleep. Among rapid eye movement (REM) sleep, increased REM pressure and elevated REM density are promising candidates for vulnerability markers. Regarding nonREM sleep, a deficit in amount of and latency until slow wave sleep during the first half of the night is a characteristic for depression. To further elucidate whether changes in the microstructure of sleep may serve as vulnerability markers we investigated the premorbid sleep composition in 21 healthy high-risk proband (HRPs) with a positive family history for affective disorders and compared HRPs with a control group of healthy subjects (HCs) without personal and family history for psychiatric disorders. The sleep electroencephalogram (EEG) was conventionally scored and submitted to a quantitative EEG analysis. The main difference in sleep characteristics between HRPs and HCs was an abnormally increased REM density. Differences in the spectral composition of sleep EEG were restricted to an increased power in the sigma frequency range. Since the HRP group comprised six unrelated and 15 related subjects we controlled for sibling effects. We could replicate the increased REM density in the group of HRPs whereas elevated power in the low sigma frequencies persisted only with approaching significance. The present study further supports elevated REM density as putative vulnerability marker for affective disorders. However, sleep EEG in our group of HRPs did not show slow wave sleep abnormalities. Ongoing follow up investigations of HRPs will clarify whether the observed increase in sigma EEG activity during nonREM sleep is of clinical relevance with respect to the likelihood to develop an affective disorder.

Aliskiren: the first renin inhibitor for clinical treatment.

The first evidence of the existence of renin was presented over 100 years ago. However, the importance of renin and the renin-angiotensin system in the pathogenesis of cardiovascular disease was only fully realized in the 1970s. It was another 20 years before the first inhibitors of renin were available for clinical research. Here, we describe the discovery and development of aliskiren, an orally active renin inhibitor, which became the first drug in its class to receive regulatory approval. In 2007, it was approved for the treatment of hypertension by the US Food and Drug Administration and the European Medicines Agency.

Dex/CRH-test response and sleep in depressed patients and healthy controls with and without vulnerability for affective disorders.

Sleep electroencephalographic (EEG) abnormalities and increased hypothalamo-pituitary-adrenal (HPA) axis activity are the most prominent neurobiological findings in depression and were suggested as potential biomarker for depression. In particular, increased rapid eye movement sleep (REM) density, deficit in slow wave sleep and excessive stress hormone response are associated with an unfavorable long-term outcome of depression. Recent studies indicate that the sleep and endocrine parameters are related to each other. This study investigated the association of sleep structure including a quantitative EEG analysis with the results of the combined dexamethasone (Dex)/corticotropin-releasing hormone (CRH)-test in 14 patients with a severe major depression, 21 healthy probands with a positive family history of depression (HRPs) and 12 healthy control subjects without personal and family history for psychiatric disorders. As expected patients with depression showed an overactivity of the HPA axis, disturbed sleep continuity and prolonged latency until slow wave sleep in the first sleep cycle. Differences in microarchitecture of sleep were less prominent and restricted to a higher NonREM sigma power in the HRP group. Dexamethasone suppressed cortisol levels were positively associated with higher NonREM sigma power after merging the three groups. We also observed an inverse association between the ACTH response to the Dex/CRH-test and rapid eye movement sleep (REM) density in HRPs, with suggestive evidence also in patients, but not in controls. This contra-intuitive finding might be a result of the subject selection (unaffected HRPs, severely depressed patients) and the complementarity of the two markers. HRPs and patients with high disease vulnerability, indicated by an elevated REM density, seem to have a lower threshold until an actual disease process affecting the HPA axis translates into depression, and vice versa. To summarize, our findings provide further evidence that the HPA axis is involved in the sleep regulation in depression. These associations, however, are not unidimensional, but dependent on the kind of sleep parameters as well as on the selection of the subjects.

Acute cortisol administration increases sleep depth and growth hormone release in patients with major depression.

Acute administration of cortisol increases non-rapid-eye movement (non-REM) sleep, suppresses rapid-eye movement (REM) sleep and stimulates growth hormone (GH) release in healthy subjects. This study investigates whether cortisol has similar endocrine and electrophysiological effects in patients with depression who typically show a pathological overactivity of the hypothalamus-pituitary-adrenal (HPA) system. Fifteen depressed inpatients underwent the combined dexamethasone/corticotropin-releasing hormone test followed by three consecutive sleep EEG recordings in which the patients received placebo (saline) and hourly injections of cortisol (1mg/KG BW). Cortisol increased duration and intensity of non-REM sleep in particular in male patients and stimulated GH release. The activity of the HPA axis appeared to influence the cortisol-induced effects on non-REM sleep and GH levels. Stimulation of delta sleep was less pronounced in patients with dexamethasone nonsuppression. In contrast, REM sleep parameters were not affected by the treatment. These data demonstrate that the non-REM sleep-promoting effects of acute cortisol injections observed in healthy controls could be replicated in patients with depression. Our results suggest that non-REM and REM sleep abnormalities during the acute state of the disease are differentially linked to the activity of the HPA axis.