Core body temperature varies according to the time of exercise without affecting orexin-A production in the dorsal hypothalamus in male rats.

Physical exercise differentially increases body temperature according to the time of day, which shows the importance of circadian rhythm in thermal regulation. Given its contribution in central pathways involved in thermoregulation, orexin A could play a role in the regulation of core body temperature during and after exercise. To test this hypothesis, we assessed the effect of exercise, performed at two times of day, on core temperature and on the amount of orexin A in the production zone, i.

Author Correction: Dual orexin receptor antagonist induces changes in core body temperature in rats after exercise.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Dual orexin receptor antagonist induces changes in core body temperature in rats after exercise.

Hypothalamic orexin neurons are involved in various physiological functions, including thermoregulation. The orexinergic system has been considered as a potent mediator of the exercise response. The present study describes how the antagonization of the orexinergic system by a dual orexin receptor antagonist (DORA) modifies the thermoregulatory process during exercise.

Anatomical and behavioral impact of a lentiviral tool tapping onto hippocampal serotonin reuptake in rats.

We aimed at the further characterization of rats in which SERT gene silencing was achieved by hippocampal injection of a lentiviral vector, carrying three si-RNA to block SERT mRNA at 66% of normal levels. Improved self-control and reduced restlessness were already demonstrated in these rats. Present further studies consisted of male adult rats, bilaterally inoculated within the hippocampus; control rats received lentivirus particles inactivated with heat.

Co-modulation of an allosteric modulator of nicotinic receptor-cholinesterase inhibitor (galantamine) and a 5-HT4 receptor agonist (RS-67333): effect on scopolamine-induced memory deficit in the mouse.

Aim: It is widely assumed that the upcoming therapeutics for Alzheimer's disease will require to act on more than one target to be effective. We investigated here whether a combination of the nicotinic receptor allosteric modulator/cholinesterase inhibitor galantamine can act synergistically with the type 4 serotonin receptor (5-HT4R) partial agonist, RS-67333, to counterbalance deficits in short- and long-term memory. To select sub-efficacious doses of both drugs, dose-response studies were first performed on the scopolamine-induced deficits of spontaneous alternation in the Y-maze task and of acquisition and retrieval processes in a passive avoidance task.

Influence of cell confluence on the cAMP signalling pathway in vascular smooth muscle cells.

The influence of cell confluence on the β-adrenoceptor (β-AR)/cAMP/phosphodiesterase (PDE) pathway was investigated in cultured rat aortic smooth muscle cells (RASMCs). Cells were plated either at low density (LD: 3·10cells/cm) or high density (HD: 3·10cells/cm) corresponding to non-confluent or confluent cells, respectively, on the day of experiment. β-AR-stimulated cAMP was monitored in real-time using the fluorescence resonance energy transfer (FRET)-based cAMP sensor, Epac2-camps.

Time-dependent impact of glutamatergic modulators on the promnesiant effect of 5-HTR blockade on mice recognition memory.

Selective antagonists at serotonin 5-HT receptors (5-HTR) improve memory performance in rodents and are currently under clinical investigations. If blockade of 5-HTR is known to increase glutamate release, only two studies have so far demonstrated an interaction between 5-HTR and glutamate transmission, but both, using the non-competitive NMDA antagonist MK-801, insensitive to variations of glutamate concentrations. In a place recognition task, we investigated here in mice the role of glutamate transmission in the beneficial effects of 5-HTR blockade (SB-271046).

An HPLC-ECD method for monoamines and metabolites quantification in cuttlefish (cephalopod) brain tissue.

The cuttlefish belongs to the mollusk class Cephalopoda, considered as the most advanced marine invertebrates and thus widely used as models to study the biology of complex behaviors and cognition, as well as their related neurochemical mechanisms. Surprisingly, methods to quantify the biogenic monoamines and their metabolites in cuttlefish brain remain sparse and measure a limited number of analytes. This work aims to validate an HPLC-ECD method for the simultaneous quantification of dopamine, serotonin, norepinephrine and their main metabolites in cuttlefish brain.

Effects of long-term methylphenidate treatment in adolescent and adult rats on hippocampal shape, functional connectivity and adult neurogenesis.

Methylphenidate (MPH) is a widely prescribed stimulant drug for the treatment of attention deficit hyperactivity disorder (ADHD) in children and adolescents. Its use in this age group raises concerns regarding the potential interference with ongoing neurodevelopmental processes. Particularly the hippocampus is a highly plastic brain region that continues to develop postnatally and is involved in cognition and emotional behavior, functions known to be affected by MPH.

Novel multitarget-directed ligands (MTDLs) with acetylcholinesterase (AChE) inhibitory and serotonergic subtype 4 receptor (5-HT4R) agonist activities as potential agents against Alzheimer's disease: the design of donecopride.

In this work, we describe the synthesis and in vitro evaluation of a novel series of multitarget-directed ligands (MTDL) displaying both nanomolar dual-binding site (DBS) acetylcholinesterase inhibitory effects and partial 5-HT4R agonist activity, among which donecopride was selected for further in vivo evaluations in mice. The latter displayed procognitive and antiamnesic effects and enhanced sAPPα release, accounting for a potential symptomatic and disease-modifying therapeutic benefit in the treatment of Alzheimer's disease.

Dual histamine H3R/serotonin 5-HT4R ligands with antiamnesic properties: pharmacophore-based virtual screening and polypharmacology.

In recent years, preclinical and clinical studies have generated considerable interest in the development of histamine H3 receptor (H3R) antagonists as novel treatment for degenerative disorders associated with impaired cholinergic function. To identify novel scaffolds for H3R antagonism, a common feature-based pharmacophore model was developed and used to screen the 17,194 compounds of the CERMN (Centre d'Etudes et de Recherche sur le Médicament de Normandie) chemical library. Out of 268 virtual hits which have been gathered in 34 clusters, we were particularly interested in tricyclic derivatives also exhibiting a potent 5HT4R affinity.

5-HT6 receptor antagonists as treatment for age-related cognitive decline.

The 5-HT6 receptor (5-HT6R) is one of the most recently discovered serotonin receptors and has received much attention after observations showing its procognition properties. Indeed, 5-HT6R appears to be a promising target to treat cognitive decline, particularly via its modulatory function of cholinergic and glutamatergic systems. 5-HT6Rs are present mostly in the central nervous system, in brain structures known to be particularly involved in memory.

Modulation of 5-HT7 receptor: effect on object recognition performances in mice.

Objective: Recent data suggest that 5-HT7 receptors (5-HT7R) are involved in memory processes and, particularly, those related to novelty-induced arousal, even though this remains so far speculative and controversial. In order to assess the role of 5-HT7R in episodic-like memory, mice were administered 5-carboxamidotryptamine (5-CT, a 5-HT1A/1B/1D/7R agonist) and/or SB-269970 (a selective 5-HT7R antagonist) immediately after the acquisition session of the novel object recognition test.

Materials And Methods: The object recognition test was performed in order to assess the effects of modulation of 5-HT7R during consolidation phase on episodic-like memory performances in mice.

Vezatin is essential for dendritic spine morphogenesis and functional synaptic maturation.

Vezatin is an integral membrane protein associated with cell-cell adhesion complex and actin cytoskeleton. It is expressed in the developing and mature mammalian brain, but its neuronal function is unknown. Here, we show that Vezatin localizes in spines in mature mouse hippocampal neurons and codistributes with PSD95, a major scaffolding protein of the excitatory postsynaptic density.

5-HT6 receptor blockade differentially affects scopolamine-induced deficits of working memory, recognition memory and aversive learning in mice.

Rationale: Blockade of 5-HT6 receptors (5-HT6R) is known to improve cognitive performances in the rodent. This improvement has been hypothesized to be the result, at least in part, of a modulation of the cholinergic neurotransmission.

Objective: We assessed the effects of 5-HT6R blockade on selected types of memory relevant to functional deficits of ageing and neurodegenerative diseases, in mice that present a scopolamine-induced cholinergic disruption of memory.

A biphasic and brain-region selective down-regulation of cyclic adenosine monophosphate concentrations supports object recognition in the rat.

Background: We aimed to further understand the relationship between cAMP concentration and mnesic performance.

Methods And Findings: Rats were injected with milrinone (PDE3 inhibitor, 0.3 mg/kg, i.

Age-dependent effects of chronic fluoxetine treatment on the serotonergic system one week following treatment.

Rationale: Selective serotonin reuptake inhibitors (SSRIs) such as fluoxetine are increasingly used for the treatment of depression in children. Limited data are, however, available on their effects on brain development and their efficacy remains debated. Moreover, previous experimental studies are seriously hampered in their clinical relevance.

Environmental enrichment improves recent but not remote memory in association with a modified brain metabolic activation profile in adult mice.

Environmental enrichment is known to improve learning and memory in adult rodents. Whereas the morphological changes underlying these beneficial effects are well documented, few studies have addressed the influence of this housing condition on the neuronal networks underlying memory processes. We assessed the effects of environmental enrichment on behavioural performances and brain metabolic activation during a memory task in mice.

Rescue of cognitive aging by long-lasting environmental enrichment exposure initiated before median lifespan.

The rescue of cognitive function through environmental enrichment (EE) during aging has been extensively documented. However, the age at onset, the duration of EE, and the cerebral mechanisms required to obtain the greatest benefits still remain to be determined. We have recently shown that EE applied for 3 mo after the median lifespan, i.

Serotonin 5-HT6 receptor blockade reverses the age-related deficits of recognition memory and working memory in mice.

Studies have shown that the blockade of 5-HT6 receptors (5-HT6R) can improve memory processes and reverse age-related spatial episodic like memory deficits. Since normal aging in the human is associated with a decline in episodic and working memory, we assessed the effect of the 5-HT6R blockade (SB-271046) on recognition memory (object recognition task) (a component of episodic like memory) in parallel to working memory (spontaneous alternation task in the T-maze) performances in young, adult, aged and senescent mice. Deficits in consolidation of non spatial recognition memory that were observed in 17- and 21-month-old mice were found to be reversed by 5-HT6R blockade.

Review of 5-HT4R ligands: state of art and clinical applications.

This article reviews the medicinal implications of 5-HT(4)R in the peripheral and central nervous systems, based on data from two hundred bibliographic references. An exhaustive compilation of molecules reported to be antagonists or agonists for 5-HT(4)R is presented, including chemical structures, binding properties and pharmacological profiles. In the last part of the review, some key concepts concerning structure-activity relationships are highlighted.

Phe369(7.38) at human 5-HT(7) receptors confers interspecies selectivity to antagonists and partial agonists.

Background And Purpose: Human and rat 5-HT(7) receptors were studied with a particular emphasis on the molecular interactions involved in ligand binding, searching for an explanation to the interspecies selectivity observed for a set of compounds. We performed affinity studies, molecular modelling and site-directed mutagenesis, with special focus on residue Phe(7.38) of the human 5-HT(7) receptor [Cys(7.

Novel antagonists of serotonin-4 receptors: synthesis and biological evaluation of pyrrolothienopyrazines.

Based on the definition of a 5-HT(4) receptor antagonist pharmacophore, a series of pyrrolo[1,2-a]thieno[3,2-e] and pyrrolo[1,2-a]thieno[2,3-e] pyrazine derivatives were designed, prepared, and evaluated to determine the properties necessary for high-affinity binding to 5-HT(4) receptors. The compounds were synthesized by substituting the chlorine atom of the pyrazine ring with various N-alkyl-4-piperidinylmethanolates. They were evaluated in binding assays with [(3)H]GR113808 (1) as the 5-HT(4) receptor radioligand.