The serotonin-N-acetylserotonin–melatonin pathway as a biomarker for autism spectrum disorders

Elevated whole-blood serotonin and decreased plasma melatonin (a circadian synchronizer hormone that derives from serotonin) have been reported independently in patients with autism spectrum disorders (ASDs). Here, we explored, in parallel, serotonin, melatonin and the intermediate N-acetylserotonin (NAS) in a large cohort of patients with ASD and their relatives. We then investigated the clinical correlates of these biochemical parameters. Whole-blood serotonin, platelet NAS and plasma melatonin were assessed in 278 patients with ASD, their 506 first-degree relatives (129 unaffected siblings, 199 mothers and 178 fathers) and 416 sex- and age-matched controls. We confirmed the previously reported hyperserotonemia in ASD (40% (35–46%) of patients), as well as the deficit in melatonin (51% (45–57%)), taking as a threshold the 95th or 5th percentile of the control group, respectively. In addition, this study reveals an increase of NAS (47% (41–54%) of patients) in platelets, pointing to a disruption of the serotonin-NAS–melatonin pathway in ASD. Biochemical impairments were also observed in the first-degree relatives of patients. A score combining impairments of serotonin, NAS and melatonin distinguished between patients and controls with a sensitivity of 80% and a specificity of 85%. In patients the melatonin deficit was only significantly associated with insomnia. Impairments of melatonin synthesis in ASD may be linked with decreased 14-3-3 proteins. Although ASDs are highly heterogeneous, disruption of the serotonin-NAS–melatonin pathway is a very frequent trait in patients and may represent a useful biomarker for a large subgroup of individuals with ASD

Dopamine acting at D1-like, D2-like and α1-adrenergic receptors differentially modulates theta and gamma oscillatory activity in primary motor cortex

The loss of dopamine (DA) in Parkinson’s is accompanied by the emergence of exaggerated theta and beta frequency neuronal oscillatory activity in the primary motor cortex (M1) and basal ganglia. DA replacement therapy or deep brain stimulation reduces the power of these oscillations and this is coincident with an improvement in motor performance implying a causal relationship. Here we provide in vitro evidence for the differential modulation of theta and gamma activity in M1 by DA acting at receptors exhibiting conventional and non-conventional DA pharmacology. Recording local field potentials in deep layer V of rat M1, co-application of carbachol (CCh, 5 μM) and kainic acid (KA, 150 nM) elicited simultaneous oscillations at a frequency of 6.49 ± 0.18 Hz (theta, n = 84) and 34.97 ± 0.39 Hz (gamma, n = 84). Bath application of DA resulted in a decrease in gamma power with no change in theta power. However, application of either the D1-like receptor agonist SKF38393 or the D2-like agonist quinpirole increased the power of both theta and gamma suggesting that the DA-mediated inhibition of oscillatory power is by action at other sites other than classical DA receptors. Application of amphetamine, which promotes endogenous amine neurotransmitter release, or the adrenergic α1-selective agonist phenylephrine mimicked the action of DA and reduced gamma power, a result unaffected by prior co-application of D1 and D2 receptor antagonists SCH23390 and sulpiride. Finally, application of the α1-adrenergic receptor antagonist prazosin blocked the action of DA on gamma power suggestive of interaction between α1 and DA receptors. These results show that DA mediates complex actions acting at dopamine D1-like and D2-like receptors, α1 adrenergic receptors and possibly DA/α1 heteromultimeric receptors to differentially modulate theta and gamma activity in M1

Introduction to multimodal compression of biomedical data

International audienceno abstrac

Compétition pour l'azote entre arbre et herbe dans des plantations de noisetier (Corylus avellana L.) et de merisier (Prunus avium L.)

Tree-on-pasture plantation and management for quality timber are studied in France and Western Europe from ten years about. Studies have mainly concerned tree establisment, protection, thinning and pruning during early growth. This article concerns the effect of adult trees (Corylus avellana and Prunus avium) and grass association on nitrogen nutrition of both canopies, as to compare to monocrops. N nutrition level of the intercropped grass was not affected by the distance from the tree, no matter the light transmission rate was. However, due to increasing windspeed from inside to outside the plantation, grass N nutrition was frequently lower on the monocropped grass. Tree N nutrition suffered the presence of grass while the light transmission rate at grass level was more than 65%, amount of broadcasted N fertilizer less than 25 kg ha-1 and localised N absent. Girth growth of both species were closely related to the ratio "Leaf N content per unit of weight / pre-dawn water potential".La culture d'arbres forestiers à bois précieux à faible densité dans des prairies pâturées fait l'objet de recherches et de mises au point techniques depuis une dizaine d'années en France et en Europe de l'Ouest. Elle concerne surtout la période d'installation et de formation des arbres et leur protection contre la dent des herbivores. Le présent article traite de la nutrition azotée de l'herbe et de l'arbre, associés ou en culture pure, pour identifier d'éventuels effets de compétition ou d'amélioration pour l'absorption de l'azote. La nutrition azotée de l'herbe dans la plantation se révèle peu sensible à la proximité des arbres; toutefois, dans un site venté, la présence des arbres crée un microclimat favorable à une meilleure nutrition. Dans des plantations à faible densité, noisetiers et merisiers ont montré un net fléchissement de leur nutrition azotée en présence d'herbe faiblement ou pas fertilisée, en comparaison d'arbres maintenus sans herbe depuis la plantation ou désherbés récemment. Des relations fortes ont été établies entre les croissances annuelles en circonférence des arbres et le rapport "teneur azotée foliaire pondérale / potentiel hydrique"

Impurity density gradient influence on trapped particle modes

International audienceThe effect of the presence of an impurity species on the trapped particle turbulence is studied using the gyro-bounce kinetic code TERESA, which allows the study of Trapped Electron Modes and Trapped Ion Modes. The impurity species is treated self-consistently and its influence on the nature of the turbulence, ion driven or electron driven, is investigated. It is found that the presence of heavy impurities with a flat density profile tends to stabilize the both electron and ion modes, whereas a peaked or hollow impurity density profile can change the turbulence from an electron driven turbulence to an ion driven turbulence. The effect of the turbulence regime on impurity transport is studied