Chronic escitalopram treatment attenuated the accelerated rapid eye movement sleep transitions after selective rapid eye movement sleep deprivation: a model-based analysis using Markov chains

BackgroundShortened rapid eye movement (REM) sleep latency and increased REM sleep amount are presumed biological markers of depression. These sleep alterations are also observable in several animal models of depression as well as during the rebound sleep after selective REM sleep deprivation (RD). Furthermore, REM sleep fragmentation is typically associated with stress procedures and anxiety. The selective serotonin reuptake inhibitor (SSRI) antidepressants reduce REM sleep time and increase REM latency after acute dosing in normal condition and even during REM rebound following RD. However, their therapeutic outcome evolves only after weeks of treatment, and the effects of chronic treatment in REM-deprived animals have not been studied yet.ResultsChronic escitalopram- (10 mg/kg/day, osmotic minipump for 24 days) or vehicle-treated rats were subjected to a 3-day-long RD on day 21 using the flower pot procedure or kept in home cage. On day 24, fronto-parietal electroencephalogram, electromyogram and motility were recorded in the first 2 h of the passive phase. The observed sleep patterns were characterized applying standard sleep metrics, by modelling the transitions between sleep phases using Markov chains and by spectral analysis.Based on Markov chain analysis, chronic escitalopram treatment attenuated the REM sleep fragmentation [accelerated transition rates between REM and non-REM (NREM) stages, decreased REM sleep residence time between two transitions] during the rebound sleep. Additionally, the antidepressant avoided the frequent awakenings during the first 30 min of recovery period. The spectral analysis showed that the SSRI prevented the RD-caused elevation in theta (5 inverted question mark9 Hz) power during slow-wave sleep. Conversely, based on the aggregate sleep metrics, escitalopram had only moderate effects and it did not significantly attenuate the REM rebound after RD.ConclusionIn conclusion, chronic SSRI treatment is capable of reducing several effects on sleep which might be the consequence of the sub-chronic stress caused by the flower pot method. These data might support the antidepressant activity of SSRIs, and may allude that investigating the rebound period following the flower pot protocol could be useful to detect antidepressant drug response. Markov analysis is a suitable method to study the sleep pattern

Luminescent Tris(8-hydroxyquinolates) of Bismuth(III)

Luminescent homoleptic bismuth(III) complexes have been synthesized by adding several functionalized 8-hydroxyquinolate ligands to bismuth(III) chloride in a 3:1 mole ratio in either ethanol or tetrahydrofuran (THF) solvent. These complexes have been characterized by single-crystal X-ray diffraction (XRD) analysis, UV-vis spectroscopy, fluorescence spectroscopy, and density functional theory (DFT) calculations to determine their structures and photophysical properties. Reversible dimerization of the mononuclear tris(hydroxyquinolate) complexes was observed in solution and quantified using UV-vis spectroscopy. The fluorescence spectra show a blue shift for the monomer compared with homoleptic aluminum(III) hydroxyquinolate compounds. Four dimeric compounds and one monomeric isomer were characterized structurally. The bismuth(III) centers in the dimers are bridged by two oxygen atoms from the substituted hydroxyquinolate ligands. The more sterically hindered quinolate complex, tris(2-(diethoxymethyl)-8-quinolinato)bismuth, crystallizes as a monomer. The complexes all exhibit low-lying absorption and emission spectral features attributable to transitions between the HOMO (π orbital localized on the quinolate phenoxide ring) and LUMO (π* orbital localized on the quinolate pyridyl ring). Excitation and emission spectra show a concentration dependence in solution that suggests that a monomer-dimer equilibrium occurs. Electronic structure DFT calculations support trends seen in the experimental results with a HOMO-LUMO gap of 2.156 eV calculated for the monomer that is significantly larger than those for the dimers (1.772 and 1.915 eV). The close face to face approach of two quinolate rings in the dimer destabilizes the uppermost occupied quinolate π orbitals, which reduces the HOMO-LUMO gap and results in longer wavelength absorption and emission spectral features than in the monomer form

Éclateur 120 kV faible inductance sous pression d'hexafluorure de soufre

A three electrode type spark gap working in sulphur hexafluoride is described. Its characteristics are : operating voltage from 60 to 120 kV, maximum current 150 kA, inductance 30 nH, jitter 15 ns. The spark gap is used in the assembling of a 24 kJ-I20 kV capacitor bank. By increasing the mechanical strength of its electrodes it was possible to operate the spark gap in nitrogen up to 600 kA at 50 kV.On décrit un éclateur du type trois électrodes fonctionnant dans l'hexafluorure de soufre. Ses caractéristiques sont : tension de fonctionnement variant de 60 à 120 kV, courant maximum 150 kA, inductance 30 nH, dispersion moyenne du retard au déclenchement 15 ns. Cet éclateur est utilisé dans la construction d'un banc de condensateurs 24 kJ-120 kV. Un second éclateur du même type fonctionnant dans l'azote à 50 kV a supporté un courant de 600 kA après augmentation des dimensions et de la résistance mécanique de ses électrodes

Equilibrium potential-pH diagram for the system Mn-H2O at 25°C✝

info:eu-repo/semantics/publishe

Cellular Basis for Bimatoprost Effects on Human Conventional Outflow

The authors report for the first time dose-related responses in outflow cells that correspond to prostaglandin effects observed on conventional outflow facility. In addition, they provide evidence for endogenous prostaglandin signaling in trabecular meshwork cells using a prostamide-selective antagonist

Control of 5-hydroxytryptamine release in the dorsal raphe nucleus by the noradrenergic system in rat brain. Role of alpha-adrenoceptors

The interactions between the brainstem serotonergic (5-hydroxytryptamine, 5-HT) and noradrenergic (NA) systems are important for the pathophysiology and treatment of affective disorders. We examined the influence of -adrenoceptors on 5-HT and NA release in the rat dorsal raphe nucleus (DR) using microdialysis. 5-HT and NA concentrations in DR dialysates were virtually suppressed by TTX and increased by veratridine. The local and systemic administration of the 1-adrenoceptor antagonist prazosin reduced the DR 5-HT output but not that of NA. The maximal 5-HT reduction induced by local prazosin administration (-78% at 100 M) was more marked than by its systemic administration (-43% at 0.3 mg/kg). The local application of NA and desipramine, to increase the tone on DR 1-adrenoceptors, did not enhance 5-HT release. The local (100 M) or systemic (0.1–1 mg/kg s.c.) administration of clonidine reduced 5-HT and NA release (-48 and -79%, respectively, at 1 mg/kg), an effect reversed by RX-821002, which by itself increased both amines when given systemically. DSP-4 pretreatment prevented the effects of clonidine on 5-HT, suggesting the participation of 2-adrenoceptors on NA elements. Moreover, the systemic effect of clonidine on 5-HT (but not NA) was cancelled by lesion of the lateral habenula and by anesthesia, and was slightly enhanced by cortical transection. These data support the view that 1-adrenoceptors in the DR tonically stimulate 5-HT release, possibly at nearly maximal tone. Likewise, the 5-HT release is modulated by 2-adrenoceptors in NA neurons and in forebrain areas involved in the distal control of 5-HT neurons.Peer reviewe