Pitolisant, a wake-promoting agent devoid of psychostimulant properties: Preclinical comparison with amphetamine, modafinil, and solriamfetol

Several therapeutic options are currently available to treat excessive daytime sleepiness (EDS) in patients suffering from narcolepsy or obstructive sleep apnea. However, there are no comparisons between the various wake-promoting agents in terms of mechanism of action, efficacy, or safety. The goal of this study was to compare amphetamine, modafinil, solriamfetol, and pitolisant at their known primary pharmacological targets, histamine H3 receptors (H3R), dopamine, norepinephrine, and serotonin transporters, and in various in vivo preclinical models in relation to neurochemistry, locomotion, behavioral sensitization, and food intake. Results confirmed that the primary pharmacological effect of amphetamine, modafinil, and solriamfetol was to increase central dopamine neurotransmission, in part by inhibiting its transporter. Furthermore, solriamfetol increased levels of extracellular dopamine in the nucleus accumbens, and decreased the 3,4-dihydroxyphenyl acetic acid (DOPAC)/DA ratio in the striatum, as reported for modafinil and amphetamine. All these compounds produced hyperlocomotion, behavioral sensitization, and hypophagia, which are common features of psychostimulants and of compounds with abuse potential. In contrast, pitolisant, a selective and potent H3R antagonist/inverse agonist that promotes wakefulness, had no effect on striatal dopamine, locomotion, or food intake. In addition, pitolisant, devoid of behavioral sensitization by itself, attenuated the hyperlocomotion induced by either modafinil or solriamfetol. Therefore, pitolisant presents biochemical, neurochemical, and behavioral profiles different from those of amphetamine and other psychostimulants such as modafinil or solriamfetol. In conclusion, pitolisant is a differentiated therapeutic option, when compared with psychostimulants, for the treatment of EDS, as this agent does not show any amphetamine-like properties within in vivo preclinical models.

Modifications of biochemical parameters in blood platelets of schizophrenic and depressive patients

The blood platelet may be considered as an interesting model of the serotoninergic neuron in biology and pharmacology. We studied some platelet parameters in neuropsychiatric patients (depressive and schizophrenic ones): serotonin (5-HT) uptake was abnormal for all schizophrenics and lowered for depressive patients; uptake of mepacrine, a marker of 5-HT passive diffusion, was diminished for manic patients; MAO and glutathione peroxidase activities were modified, essentially for paranoid schizophrenics and some alterations of the platelet hydroxyindole level were noticed; during treatment with neuroleptics of antidepressants biological parameters led to 'normality'. These results are discussed with clinical data and a hypothesis is proposed to join the biological modifications of paranoid schizophrenics.

Human platelet arginase

We report here, for the first time the presence of arginase in human platelets. This enzyme has been partially purified and some of it properties studied. Its biological significance and its involvement in polyamine biosynthesis are considered.

On the presence of carnitine acetyl transferase in human platelets

The presence of carnitine acetyl transferase (E.C.2.3.1.7) activity has been found for the first time in human platelets. The enzymic activity was measured by a radiometric method based on the separation of labelled acetylcarnitine and carnitine on a cation exchange column. Carnitine acetyl transferase activity closely paralleled the activity distribution of the mitochondrial marker carnitine palmitoyl-transferase. Contrary to the marker enzyme, human platelet carnitine acetyl-transferase is rather thermosensitive: 60% of its activity is lost after 10 min when kept at 37 degree C.

[Observations on the breeding of Glossina tachinoides West., after adoption of the rabbit as an animal-host]

L'adoption du lapin comme animal hôte et la réception d'un important lot de pupes ont permis d'obtenir, depuis le début de l'année 1967, un élevage florissant de Gl. tachinoides. Malgré une intoxication accidentelle par insecticide, qui a fait tomber les effectifs à moins de 400 femelles/jour, ceux-ci dépassaient 6 mois plus tard 2.300 femelles. La longévité maximale des femelles a été de 210 jours et la production de pupes a atteint 695 pupes pour 100 femelles. La technique utilisée est susceptible d'être appliquée à un élevage en masse en vue de la production de mâles stériles

[Immunologic studies on trypanosomiases. IV. Various observations on Trypanosoma congolense]

Un antisérum contre un variant tardif de Trypanosoma congolense n'a montré aucune activité neutralisante sur un type antigénique obtenu au début de l'infection, chez un mouton infecté cycliquement. Des sérums obtenus de rats et souris 10 à 13 jours après un traitement stérilisant, effectué lors de la première parasitémie après inoculation de trypanosomes, n'ont pas montré une activité neutralisante suffisamment élevée contre le type antigénique injecté, pour que cette méthode semble intéressante pour l'obtention de sérums monovalents. Le comportement de la souche utilisée n'est en outre pas assez régulier chez le rat (à l'opposé de la souris). Un traitement de moutons au Bérénil, à forte dose, ne semble pas influencer les résultats de tests de neutralisation effectués avec du sérum peu de temps après le traitement. Quelques observations sur la persistance des anticorps contre différents types antigéniques chez des moutons sont donnés. Des expériences sur les réactions d'agglutination et de lyse avec T. congolense ont abouti à des échecs.

Towards New Anti-Inflammatory Agents: Design, Synthesis and Evaluation of Molecules Targeting XIAP-BIR2

The X-chromosome-linked inhibitor of apoptosis protein (XIAP) plays a crucial role in controlling cell survival across multiple regulated cell death pathways and coordinating a range of inflammatory signalling events. The discovery of selective inhibitors for XIAP-BIR2, able to disrupt the direct physical interaction between XIAP and RIPK2, offer promising therapeutic options for NOD2-mediated diseases like Crohn's disease, sarcoidosis, and Blau syndrome. The objective of this study was to design, synthesize, and evaluate small synthetic molecules with binding selectivity to XIAP-BIR2 domain. To achieve this, we applied an interdisciplinary drug design approach and firstly we have synthesized an initial fragment library to achieve a first XIAP inhibition activity. Then using a growing strategy, larger compounds were synthesized and one of them presents a good selectivity for XIAP-BIR2 versus XIAP-BIR3 domain, compound 20 c. The ability of compound 20 c to block the NOD1/2 pathway was confirmed in cell models. These data show that we have synthesized molecules capable of blocking NOD1/2 signalling pathways in cellulo, and ultimately leading to new anti-inflammatory compounds.